Nonverbal Oro-Motor Exercises: Do They Really Work for Phonoarticulatory Difficulties?

Abstract

Articulation disorders are deficiencies in the realization of speech sounds unrelated to organic or neurological disorders. Over the last decade, there has been a debate on the efficiency of non-verbal oro-motor exercises, which are orofacial movements programmed and organized in an intentional and coordinated way to control lips, tongue, and soft palate muscles. Of the 122 children evaluated, 52 presented articulatory difficulties. An intervention with nonverbal oro-motor exercises was applied, and children were again assessed following treatment. The results showed no differences between the experimental and control groups, either in the number of sounds that improved after this period or in the severity of difficulties (we categorized those with articulation difficulties in two to six sounds as ‘medium’ and those with difficulties in articulating more than seven sounds as ‘severe’). These results indicated that nonverbal oro-motor exercises alone are not efficient for intervention in difficulties in the realization of sounds in 4-year-old children.

Full text

Citation: Parra-López, P.;
Olmos-Soria, M.; Valero-García, A.V.
Nonverbal Oro-Motor Exercises: Do
They Really Work for
Phonoarticulatory Difficulties? Int. J.
Environ. Res. Public Health 2022,19,
5459. https://doi.org/10.3390/
ijerph19095459
Academic Editors: Eduardo Fonseca-
Pedrero and Martin Debbané
Received: 19 December 2021
Accepted: 8 April 2022
Published: 29 April 2022
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International Journal of
Environmental Research
and Public Health
Article
Nonverbal Oro-Motor Exercises: Do They Really Work for
Phonoarticulatory Difficulties?
Pablo Parra-López *, Marina Olmos-Soria and Ana V. Valero-García
Department of Developmental and Educational Psychology, Faculty of Psychology, University of Murcia,
30100 Murcia, Spain; marolmos@um.es (M.O.-S.); vanesavg@um.es (A.V.V.-G.)
*Correspondence: pabloparra@um.es; Tel.: +34-868-884-888
Abstract:
Articulation disorders are deficiencies in the realization of speech sounds unrelated to
organic or neurological disorders. Over the last decade, there has been a debate on the efficiency of
non-verbal oro-motor exercises, which are orofacial movements programmed and organized in an
intentional and coordinated way to control lips, tongue, and soft palate muscles. Of the
122 children
evaluated, 52 presented articulatory difficulties. An intervention with nonverbal oro-motor exercises
was applied, and children were again assessed following treatment. The results showed no differences
between the experimental and control groups, either in the number of sounds that improved after this
period or in the severity of difficulties (we categorized those with articulation difficulties in two to
six sounds
as ‘medium’ and those with difficulties in articulating more than seven sounds as ‘severe’).
These results indicated that nonverbal oro-motor exercises alone are not efficient for intervention in
difficulties in the realization of sounds in 4-year-old children.
Keywords:
articulation disorder; nonverbal oro-motor exercises; intervention in difficulties in articu-
lation; practice-based evidence; phonetic disorder; childhood
1. Introduction
It is common for children with typical development to err in the realization of sounds in
their speech development process, but these difficulties should give way to understandable
speech around the age of 3 years, according to the DSM-5 [
1
]. Articulatory phonetics
considers how articulatory organs produce language sounds varying in four characteristics:
the place of articulation, manner of articulation, nasality–orality, and voiced–voiceless [
2
,
3
].
Articulation disorders are difficulties in phoneme acquisition, i.e., difficulties in cor-
rectly pronouncing some phonemes or groups of phonemes, which can often cause unin-
telligible speech in the child [
4
,
5
]. In Spain, these deficits have traditionally been labeled
as ‘dyslalias’. Thus, authors such as [
6
] defined ‘dyslalia’ as a disorder in the articulation
of one or more sounds that are produced later than expected in typical development. In
this regard, functional articulation disorders should be understood as a deficit in the pro-
nunciation of phonemes produced by a delay in motor maturity, i.e., by an inadequate
function in peripheral organs of speech, without organic or neurological lesions [
4
,
7
]. Other
authors included articulation disorders within ‘phonological disorders’, following the
psycholinguistic paradigm [
2
,
8
] and the new APA conceptualization [
1
]. Following this
approach, phoneme acquisition is based on phonological knowledge and the ability to
coordinate the movements of articulatory organs such as lips, tongue, and soft palate, as
well as breathing and vocalization of speech. Hence, alterations in phonological production
are due to problems in the phonological knowledge of speech sound or to problems in
the ability to coordinate speech movements, so the phonological disorder includes both
phonological and articulation deficits [1].
From this perspective, phonetic and phonological disorders are considered to be dif-
ferent both in etiology and intervention [
9
,
10
]: the former are speech deficiencies where the
Int. J. Environ. Res. Public Health 2022,19, 5459. https://doi.org/10.3390/ijerph19095459 https://www.mdpi.com/journal/ijerph

Int. J. Environ. Res. Public Health 2022,19, 5459 2 of 13
phonetic aspect is affected because of a delay in the development of articulatory aspects
of a functional nature, while phonological disorders are a speech disorder wherein diffi-
culties are observed in auditory discrimination and phonological programming—placing
phonemes in the right order within the word [
11
,
12
]. When continuing the differentiation
of these two concepts, phonetic disorders are characterized by error stability (i.e., they do
not improve with repetition), children are usually aware of their mistakes, and these may
not appear in their writing. On the other hand, phonological disorders are characterized
by error instability; they improve with repetition, children are usually unaware of their
mistakes, and these are commonly reflected in their writing [
9
]. Children with phonetic
disorders make articulation errors both in the repetition of syllables and sounds as well as
in isolated words and in the sentence context, as they lack the necessary motor coordination
and accuracy in phonoarticulatory organs, and therefore, errors are systematic and inde-
pendent of the phonetic context. However, in children with phonological disorders, the
production of the isolated sound is usually correct, and the error pattern is not systematic
owing to the fact that these errors vary in relation to the phonetic context, e.g., a child can
have a correct production of the phoneme /k/ in the word ‘car’ but substitute /t/ for it in
the word ‘chocolate’, producing ‘chotolate’ [
12
,
13
]. Furthermore, in most cases, the child
presents both types of errors [
12
–
14
]. The most problematic phonemes are those requiring
a more precise motor accuracy, such as phonemes /r/, either simple or multiple, and the
consonant groups [
15
,
16
]. Since, in order to be pronounced, they require fine coordination
and control of the muscular groups involved [
17
], these can be long-lasting, as found in
Preston’s study [
18
] with a group of children with articulation disorders whose average
age was 4.6 years and whose deficiencies lasted for 4 years.
However, other authors have claimed that there should be a division in the denom-
ination of phonological disorders to differentiate articulation disorders. These include
those substitutions or distortions of isolated sounds in all phonetic contexts during imi-
tation, elicitation, or spontaneous speech tasks [
19
]. Articulation disorders are classified
as developmental, auditory, organic, and functional [
4
,
12
,
20
]. Among the different causes,
studies have related them to memory problems, as well as to immediate auditory memory,
immediate visual memory, and motor speed, together with attention deficit [
21
]. Some
speech therapy textbooks mention the following as etiological factors: the lack of control
of fine motor skills (articulation of speech requires large motor skills), deficits in auditory
perception and discrimination, low linguistic stimulation, bilingualism, psychological fac-
tors (overprotection, traumatic situations, etc.), atypical swallowing, intellectual deficiency,
etc. [
22
–
24
]. In most cases, these factors are not present in isolation, but several appear
together [
12
,
25
]. Articulation problems can affect the socio-emotional development of the
child so that they turn shy, anxious, afraid to speak, and aggressive, and there is a decrease
in social relations resulting in social isolation [
26
,
27
]. Recently, as an integration of both
(phonetic and phonological) perspectives, [
28
] proposed the concept of ‘articulatory gesture’
based on the Articulatory Phonology Model [
29
], which, in turn, lies in Dynamic System
Theory. They propose that the development of speech sounds in children is achieved
through the development of speech perception but also the maturation of articulatory
gestures. They consider that ‘all levels involved in speech production are part of a com-
plex system with processing stages that are highly integrated and coupled at different
time scales’.
As for intervention, some authors have considered common speech therapy practices
for these difficulties, directed at auditory discrimination, orofacial motricity, and breathing
and blowing. Once the sound is achieved, it should be integrated into speech by repetition
and generalized in the child’s elicited language (for example, with images). Finally, it
should be integrated into their spontaneous language [
14
,
15
]. The causes of articulation
disorders are multifactorial; therefore, their treatment must also be multidimensional. For
this reason, we suggest analyzing the efficiency of intervention techniques in an isolated
way, without meaning that the treatment should only be based on nonverbal oro-motor
exercises. In the psycholinguistic model, these difficulties are considered to be ‘phonological

Int. J. Environ. Res. Public Health 2022,19, 5459 3 of 13
simplification processes’ or phonological processes that are conceptualized in a set of mental
operations that children use to simplify adult speech [
30
,
31
], i.e., to simplify the adult sound
by adapting it to their possibilities of expression. Some authors have offered interesting
discussions on this topic [
32
,
33
]. These processes can be grouped into three categories:
(1) processes related to the syllabic structure, where the child simplifies any syllable to
adapt it to their way of speaking according to their developmental level; (2) substitute
processes, when the child changes a contractive segment for a different one that is easier to
pronounce; and (3) assimilatory processes that appear when children make a sound similar
to another in the same word—for example, ‘totolate’ for ‘chocolate’ [2,8,30,31,34].
Other authors have included nonverbal oro-motor exercises in the treatment of articu-
lation disorders from the phonological standpoint [
31
]. When difficulties are articulatory
and perceptive, these authors proposed intervention with two aims; the first focused on
perceptual development with exercises associating sounds and words with related images,
and the second pursued phonoarticulatory elicitation. This includes the initial assessment
of the session, nonverbal oro-motor exercises, modeling, training in location placement,
and shaping and reading of words and phrases. The debate is still ongoing regarding
the use of nonverbal oro-motor exercises, which are understood as important training to
perform and articulate learned movements with the tongue, lips, jaw, and facial gestures
with the aim of producing phonemes and words [
35
]. According to the Evidence-Based
Practice (EBP) model of the ASHA, we should integrate empirical evidence from research
with the professional experience of speech therapists and the characteristics of the patient
in the process of making clinical decisions. Thus, some authors have claimed that non-
verbal oro-motor exercises are still an ideal treatment for articulation disorders [
36
–
39
].
Indeed, there are few studies in speech therapy scientifically supporting interventions with
nonverbal oro-motor exercises [
13
]. In contrast, several studies have empirically analyzed
relations between fine motricity and language developmental disorders and considered
nonverbal oro-motor exercises not useful for speech disorders, and they were dubious re-
garding their efficiency [
40
–
44
]. Thus, Lof [
41
,
42
] reviewed interventions with non-speech
oral movements and concluded that no evidence exists that these exercises improve the
child’s speech, although he also pointed out that because a group of techniques is used
at the same time as the nonverbal oro-motor exercises, it is, therefore, difficult to know
the precise role of these movements in the child’s improvement of sound realization. In
addition, this author questioned the scientific rigor of these studies and stressed the need
for research using individual treatments to prove their effectiveness. In line with these
authors, a study was carried out in the US where speech therapists were asked whether
they used nonverbal oro-motor exercises and why with results showing that 85% of Ameri-
can professionals considered them useful for the intervention in the production of speech
sounds [
43
]. Similarly, Furlong [
45
] found that the traditional articulation approach in
conjunction with minimal pairs was the most common therapy used for speech sound
disorders by the Australian SLPs they interviewed. Nevertheless, when American Uni-
versity speech therapists were asked that same question, the results showed that 25% of
professors recommended nonverbal oro-motor exercises, and 75% did not, warning that
their effectiveness is in question [46,47].
In Spain, some authors consider nonverbal oro-motor exercises an effective tool [
35
,
48
],
and some even use them when taking the phonological approach [
31
]. However, other
authors have claimed that nonverbal oro-motor exercises are not useful [
8
,
11
]. In the
most recent review on the efficiency of nonverbal oro-motor exercise programs and verbal
treatments based on phonemes, syllables, and words, Ygual-Fernández [
47
] concluded
there are no arguments to support the use of nonverbal oro-motor exercises.
Therefore, in this study, we analyzed the efficiency of nonverbal oro-motor exercises
for the acquisition of phonemes in children with articulation difficulties at 4 years of age. A
second aim was to determine which phonemes or groups of phonemes nonverbal oro-motor
exercises are more efficient. The third objective was to analyze whether the benefits are the
same regardless of the severity of the difficulties.

Int. J. Environ. Res. Public Health 2022,19, 5459 4 of 13
Thus, our first hypothesis is that there will be differences between the experimental
and control groups in the number of difficulties in the realization of sounds once the
intervention with nonverbal oro-motor exercises is implemented. The second hypothesis is
that nonverbal oro-motor exercises will improve in a differential way the production of the
different sounds. The third hypothesis is that nonverbal oro-motor exercises will be more
efficient in addressing more severe difficulties in realizing sounds.
2. Materials and Methods
2.1. Participants
Authorization was requested from the center and from the parents of students without
disabilities in the 2nd year of Early Childhood Education in two preschools in Murcia,
one in the city center and another on the city outskirts. Both schools are part of an urban
area. Of all the parents, 99% approved of their children taking part in the study, as they
were offered a report on their children’s speech development at the end. The sample
comprised 122 participants, 60 boys (49%) and 62 girls (51%) with a mean age of 4 years
and 7 months (M= 55, 28 months, range = 11, minimum = 50 and maximum = 61). The
children evaluated had a typical development and belonged to families with a medium
socioeconomic level. For this study, 4-year-olds were chosen, as they are usually the ones
who simplify speech and have completed the phonological system of contrasts and the full
development of their perceptual capacity [
49
] and also developed adequate motor skills to
articulate the entire specific phonetic range of their native language [12].
Table 1shows the distribution of participants in both centers. Children who had
difficulties in producing two or more phonemes were divided into two types, depending
on the number of difficulties in the realization of sounds. Thus, we classified difficulties
as moderate when the children had problems with between two and six sounds and
severe when they had difficulties with more than seven sounds. Half of the participants
in each category were randomly distributed to the control or experimental groups. The
number of children who had articulatory difficulties with more than two sounds was 55.
One participant abandoned school during the study, and two children were eliminated
for having a large number of articulation difficulties (more than 17 sounds) and in the
assessment showed organic problems, although undiagnosed. Thus, the final number of
participants was 52: 26 of these were assigned to the experimental group and 26 to the
control group. As mentioned above, half of the children with moderate difficulties were
assigned to the experimental group and the other half to the control group (randomly
distributed by the other variables of sex and classroom). Similarly, children with severe
difficulties were distributed between the experimental and control groups. There were
seven experimental subgroups: five with four children and two with three children.
Table 1. Distribution of participants by school and experimental and control groups.
Schools Number Number of Children with Difficulties in the
Realization of Sounds
Moderate
Difficulties
Severe
Difficulties
School 1 N50 24 (−1) 16 (−1) 8
Experimental G 12 (−1) 8 (−1) 4
Control G 12 8 4
Boys 28 15 10 5
Girls 22 9 (−1) 6 (−1) 3
School 2 N72 31 (−2) 21 10 (−2)
Experimental G 16 (−1) 10 6 (−1)
Control G 15 (−1) 11 4 (−1)
Boys 32 17 (−1) 12 5 (−1)
Girls 40 14 (−1) 9 5 (−1)
Total 122 55 (−3) 37 (−1) 18 (−2)
Note. From the initial 55 children, 3 were eliminated, as explained in the text.

Int. J. Environ. Res. Public Health 2022,19, 5459 5 of 13
2.2. Measures and Procedure
Difficulties in the realization of sounds were assessed using the Induced Phonological
Register [
50
]. This is a test based on the adult’s ideal model of pronunciation of the
phoneme, and the sound not matching adult speech is considered an articulatory difficulty.
The test evaluates induced and repeated language of children. They must name different
drawings. In case of error, the child must repeat the word that the evaluator indicates. The
material comprises 57 drawings of objects that cover the broad phonological spectrum of
the Spanish language, although two more images (cross and dragon—‘cruz’ and ‘dragon’
in Spanish) were introduced to complete the consonant groups with /r/. The test was
administered through a PowerPoint presentation to make the evaluation more dynamic. It
took around 20 min to complete.
The test was administered individually in the speech therapy classroom. In order to
familiarize the child with the situation and prior to the evaluation, the child was asked
general questions. Upon completion, they were given drawings to color as a reward.
All tests were recorded. The Induced Phonological Record was used in both the pretest
and post-test. On completion of the test, children were asked to repeat isolated syllables,
including phonemes that were incorrectly pronounced even in word repetition. A basic
exploration with nonverbal oro-motor exercises was made (tongue moving up and down,
around the lips, inside the mouth, toward the right and left sides of the mouth, etc.), noting
whether pronunciation was correct, to eliminate the possibility of an organic deficiency.
For this study, we were only interested in sounds that the child could not produce in either
naming or repetition [
51
], as this indicated a disorder of a phonetic and not phonological
nature. We decided to consider not only single phonemes but also the diphthongs, inverse
phonetic groups, and consonant groups included in the test.
Once participants were evaluated and placed in different groups, the intervention with
experimental groups began. This consisted of a series of 30 min sessions with nonverbal
oro-motor exercises. It should be noted that these exercises produce fatigue, so intervention
sessions should not be too long. These sessions occurred twice a week for 3 months in
the school center, and each participant completed 24 sessions. Interventions were made in
groups of three or four participants, depending on the subgroup, and in the soundproofed
and specially equipped speech therapy room.
The intervention focused exclusively on the use of nonverbal oro-motor exercises, i.e.,
programmed orofacial movements organized in an intentional and coordinated form [
52
,
53
].
In order to choose the movements, we used the Ciceron Program for the acquisition and de-
velopment of articulatory ability [
54
]. This program includes nonverbal oro-motor exercises
for each phoneme, and we selected the most common movements in different phonemes.
All children performed the complete set of exercises, regardless of the articulation difficul-
ties presented (see Table 2). In all sessions, the exercises performed were noted.
The modeling of nonverbal oro-motor exercises with a mirror was used. Moreover,
social and material reinforcement (drawings, stickers, etc.) were used to motivate children
when the sessions were finished. After approximately 3 months, all participants in both
groups were again assessed with the Induced Phonological Register.
2.3. Data Analyses
First, the frequencies of articulation difficulties in the pretest assessment were analyzed.
In order to evaluate intervention efficiency, a repeated measures Generalized Linear Model
(GLM) was chosen, taking the group as fixed factors and taking as response variables the
number of sounds with articulation difficulties in the pretest and post-test assessments of
experimental and control group participants. We used a repeated-measures model as there
was a pretest and a post-test assessment. The data were analyzed using IBM SPSS Statistics
for Windows (IBM Version 22.0, Armonk, New York, NY, USA).

Int. J. Environ. Res. Public Health 2022,19, 5459 6 of 13
Table 2. Nonverbal oro-motor exercises selected for intervention.
N◦Nonverbal Oro-Motor Exercise Articulatory Organ
1 Open mouth and closed mouth
2 Lips making an angry position (lips to the front) and a smile position (not showing teeth)
3 Upper lip covers lower lip and vice versa Lips
4 Upper teeth bite lower lip and vice versa
5Join upper and lower teeth and show these in the mirror, i.e., opening lips wide and then
hiding the teeth behind the lips
6Lick the upper teeth from the outer side first and from the inner side later. The same with the
lower teeth
7 Bring the tongue in and out of mouth
8 Put the tip of the tongue at the front and back of the incisor superior teeth
9Put the tongue in a wide shape (between the teeth) outside the mouth and then in a narrow
shape outside the mouth
10 Stick out the tongue as far as possible, moving it up and down
11 Move the tongue to the right and left of the corner of the mouth without it touching lips
12 Touch the upper molar teeth with the tip of the tongue, then the lower molar teeth
13 Move the tongue toward the right inside the mouth—as if it was a sweet—and then to the left
14 Make a clicking sound with the tongue—like a horse trot
15 Move the tip of the tongue along the roof of the mouth (from the hard to the soft palate) and
then along the floor of the mouth (from the inferior tooth socket to the base of the mouth)
16 Blow raspberries with lips and tongue
17 Make the gesture of yawning and close the mouth
18 Make the gesture of kissing noisily and smile
19 Inflate the cheeks, release air, and then suck in the cheeks Facial Gesture
20 Inflate the right cheek and then the left one quickly
3. Results
As mentioned earlier, this work aimed to study the usefulness of training in nonverbal
oro-motor exercises in the intervention of articulatory difficulties.
In order to achieve this aim, it was necessary to first prove whether training with
nonverbal oro-motor exercises improved the articulation of sounds and if so, to verify in
which phonemes they are most effective.
The results showed that the nasal and occlusive phonemes are the first that all children
acquire in the Spanish language since 100% emitted them correctly. Of the participants, 80%
had fricative (/s/, /z/, /f/, /j/ and /y/), affricate (/ch/), and lateral (/l/, /ll/) phonemes.
However, this percentage decreased to 66% for non-lateral (/r/ and /rr/) liquids, especially
the multiple vibrant phoneme /rr/, as this was one of the most difficult to produce (see
Figure 1). Most children had acquired diphthongs and inverse phonemes, while consonant
groups are late to appear, and only 80% of assessed participants had acquired them.
Once children were evaluated, non-produced sound frequencies were calculated. In
Figure 1, it is clearly observed that non-lateral liquid phonemes were the most difficult to
pronounce (approximately 20%), as well as inverse alveolars (/al/, /ar/, /as/). Similarly,
consonant groups con /l/ and /r/ were the most difficult for 4-year-olds to acquire.
In order to analyze the effect of the nonverbal oro-motor exercises, a repeated measure
analysis was carried out where the fixed factor was group (experimental versus control),
and dependent variables were pre- and post-test evaluation. There were no significant
differences following intervention between the experimental and control groups in the
number of non-produced sounds F(1, 48) = 0.335; p= 0.565; n
p2
= 0.007; f
2
=.088; therefore,
both groups improved, but not because of the oro-motor exercises (see Table 3). A post
hoc power calculation was performed with G*Power. Given that an effect size of d = 0.4
is a good first estimate of the smallest effect size of interest in psychological research, we
needed over 50 participants for a simple comparison of two within-participants conditions
to run a study with 80% power (with alpha = 0.05).

Int. J. Environ. Res. Public Health 2022,19, 5459 7 of 13
Int. J. Environ. Res. Public Health 2022, 19, x FOR PEER REVIEW 7 of 13
Figure 1. Frequency percentages of non-produced sounds in the pretest assessment.
Once children were evaluated, non-produced sound frequencies were calculated. In
Figure 1, it is clearly observed that non-lateral liquid phonemes were the most difficult to
pronounce (approximately 20%), as well as inverse alveolars (/al/, /ar/, /as/). Similarly,
consonant groups con /l/ and /r/ were the most difficult for 4-year-olds to acquire. In order
to analyze the effect of the nonverbal oro-motor exercises, a repeated measure analysis
was carried out where the fixed factor was group (experimental versus control), and de-
pendent variables were pre- and post-test evaluation. There were no significant differ-
ences following intervention between the experimental and control groups in the number
of non-produced sounds F(1, 48) = 0.335; p = 0.565; np2 = 0.007; f2 =.088; therefore, both
groups improved, but not because of the oro-motor exercises (see Table 3). A post hoc
power calculation was performed with G*Power. Given that an effect size of d = 0.4 is a
good first estimate of the smallest effect size of interest in psychological research, we
needed over 50 participants for a simple comparison of two within-participants conditions
to run a study with 80% power (with alpha = 0.05).
Table 3. Number of non-produced sounds for the experimental and control groups in the pretest
and post-test assessment.
Severity
Group
Mean
SD
N
Pre
2
Control
3.50
1.54
20
Experimental
3.47
1.42
17
3
Control
10.83
2.04
6
Experimental
10.67
2.34
9
Post
2
Control
1.85
2.06
20
Experimental
2.00
1.90
17
3
Control
4.33
2.16
6
Experimental
5.67
3.24
9
Note. Severity 2 refers to participants who had difficulties with between two and six sounds at the
pretest assessment (moderate deficiency). Severity 3 refers to those participants who had articula-
tion difficulties with more than seven sounds at the pretest (severe deficiency).
In order to respond to another of our research aims, i.e., to determine in which sounds
nonverbal oro-motor exercises were more effective, non-produced sounds were analyzed
0
5
10
15
20
25
30
35
ch f l ll k g s z r rr au an as al ar pl fl bl cl gl cr fr tr gr pr br dr
Figure 1. Frequency percentages of non-produced sounds in the pretest assessment.
Table 3.
Number of non-produced sounds for the experimental and control groups in the pretest and
post-test assessment.
Severity Group Mean SD N
Pre
2Control 3.50 1.54 20
Experimental 3.47 1.42 17
3Control 10.83 2.04 6
Experimental 10.67 2.34 9
Post
2Control 1.85 2.06 20
Experimental 2.00 1.90 17
3Control 4.33 2.16 6
Experimental 5.67 3.24 9
Note. Severity 2 refers to participants who had difficulties with between two and six sounds at the pretest
assessment (moderate deficiency). Severity 3 refers to those participants who had articulation difficulties with
more than seven sounds at the pretest (severe deficiency).
In order to respond to another of our research aims, i.e., to determine in which sounds
nonverbal oro-motor exercises were more effective, non-produced sounds were analyzed
both in the initial evaluation and in the evaluation following intervention, i.e., the most
difficult phonemes were considered (/s/, /z/, /r/, /rr/) as well as inverse phonemes
(/an/, /ar/, /as/, /az/), and consonant groups with /l/ (/bl/, /cl/, /fl/, /gl/ and /pl/)
and with /r/ (/br/, /cr/, /dr/, /fr/, /gr/, /pr/ and /tr/) (see Figures 2and 3).
In no case were there significant differences between the control and experimental
groups, indicating that nonverbal oro-motor exercises were not especially efficient for diffi-
culties with any specific kind of phonemes. Nor were differences found when phonemes
were grouped in alveolar (/s/, /r/ and /rr/), inverse (/an/, /ar/, /as/ and /az/), fricative
(s y z), and consonant groups with /l/ and /r/. We finally grouped non-lateral liquids
(/r/ and /rr/) and again found the same result for non-significant differences between
the experimental and control groups. In summary, the results showed that both groups
(experimental and control) improved in the realization of sounds, regardless of intervention.
Our third aim was to analyze the efficiency of nonverbal oro-motor exercises de-
pending on the severity of the articulation difficulties. Although there were significant
differences in the realization of sounds in the pretest and post-test between participants
with severe deficits and those with moderate deficits in a repeated measures GLM test
(
F(1, 48) = 86.528
;p< 0.001; n
p2
= 0.643; f
2
= 1000), this effect was not due to the inter-
vention, as an interaction between severity and treatment groups showed no significant
differences (see Figure 4).

Int. J. Environ. Res. Public Health 2022,19, 5459 8 of 13
Int. J. Environ. Res. Public Health 2022, 19, x FOR PEER REVIEW 8 of 13
both in the initial evaluation and in the evaluation following intervention, i.e., the most
difficult phonemes were considered (/s/, /z/, /r/, /rr/) as well as inverse phonemes (/an/,
/ar/, /as/, /az/), and consonant groups with /l/ (/bl/, /cl/, /fl/, /gl/ and /pl/) and with /r/ (/br/,
/cr/, /dr/, /fr/, /gr/, /pr/ and /tr/) (see Figure 2; Figure 3).
Figure 2. Number of non-produced sounds in difficult and inverse phonemes in the pretest and
post-test in experimental and control groups.
Figure 3. Number of non-produced sounds in consonant groups in the pretest and post-test in ex-
perimental and control groups.
In no case were there significant differences between the control and experimental
groups, indicating that nonverbal oro-motor exercises were not especially efficient for dif-
ficulties with any specific kind of phonemes. Nor were differences found when phonemes
0
10
20
30
40
50
60
bl
Pre
bl
Post
br
Pre
br
Post
cl
Pre
cl
Post
Cr
pre
Cr
post
dr
pre
dr
post
fl
Pre
fl
Post
fr
Pre
fr
Post
gl
Pre
gl
Post
gr
Pre
gr
Post
pl
Pre
pl
Post
pr
Pre
pr
Post
tr
Pre
tr
Post
Numbers of non-produced sounds in consonant groups
Experimental Control
Figure 2.
Number of non-produced sounds in difficult and inverse phonemes in the pretest and
post-test in experimental and control groups.
Int. J. Environ. Res. Public Health 2022, 19, x FOR PEER REVIEW 8 of 13
both in the initial evaluation and in the evaluation following intervention, i.e., the most
difficult phonemes were considered (/s/, /z/, /r/, /rr/) as well as inverse phonemes (/an/,
/ar/, /as/, /az/), and consonant groups with /l/ (/bl/, /cl/, /fl/, /gl/ and /pl/) and with /r/ (/br/,
/cr/, /dr/, /fr/, /gr/, /pr/ and /tr/) (see Figure 2; Figure 3).
Figure 2. Number of non-produced sounds in difficult and inverse phonemes in the pretest and
post-test in experimental and control groups.
Figure 3. Number of non-produced sounds in consonant groups in the pretest and post-test in ex-
perimental and control groups.
In no case were there significant differences between the control and experimental
groups, indicating that nonverbal oro-motor exercises were not especially efficient for dif-
ficulties with any specific kind of phonemes. Nor were differences found when phonemes
0
10
20
30
40
50
60
bl
Pre
bl
Post
br
Pre
br
Post
cl
Pre
cl
Post
Cr
pre
Cr
post
dr
pre
dr
post
fl
Pre
fl
Post
fr
Pre
fr
Post
gl
Pre
gl
Post
gr
Pre
gr
Post
pl
Pre
pl
Post
pr
Pre
pr
Post
tr
Pre
tr
Post
Numbers of non-produced sounds in consonant groups
Experimental Control
Figure 3.
Number of non-produced sounds in consonant groups in the pretest and post-test in
experimental and control groups.
In order to improve the results analysis, the means before and after intervention
were compared following the repeated measures model. As reflected in Figure 5, there
was a parallel linear decrease in the number of non-produced sounds for both groups.
We observed that intervention did not have any effect on the participants‘ realization of
sounds, as the differences between the pretest and post-test following intervention were
not significant regarding the severity of participant difficulty measured by the number of
non-produced sounds.

Int. J. Environ. Res. Public Health 2022,19, 5459 9 of 13
Int. J. Environ. Res. Public Health 2022, 19, x FOR PEER REVIEW 9 of 13
were grouped in alveolar (/s/, /r/ and /rr/), inverse (/an/, /ar/, /as/ and /az/), fricative (s y
z), and consonant groups with /l/ and /r/. We finally grouped non-lateral liquids (/r/ and
/rr/) and again found the same result for non-significant differences between the experi-
mental and control groups. In summary, the results showed that both groups (experi-
mental and control) improved in the realization of sounds, regardless of intervention.
Our third aim was to analyze the efficiency of nonverbal oro-motor exercises depend-
ing on the severity of the articulation difficulties. Although there were significant differ-
ences in the realization of sounds in the pretest and post-test between participants with
severe deficits and those with moderate deficits in a repeated measures GLM test (F(1, 48)
= 86.528; p < 0.001; np2= 0.643; f2= 1000), this effect was not due to the intervention, as an
interaction between severity and treatment groups showed no significant differences (see
Figure 4).
Figure 4. Mean of non-produced phonemes in the pretest and post-test depending on the severity
of articulation difficulties (moderate difficulties: 2; severe difficulties: 3).
In order to improve the results analysis, the means before and after intervention were
compared following the repeated measures model. As reflected in Figure 5, there was a
parallel linear decrease in the number of non-produced sounds for both groups. We ob-
served that intervention did not have any effect on the participants‘ realization of sounds,
as the differences between the pretest and post-test following intervention were not sig-
nificant regarding the severity of participant difficulty measured by the number of non-
produced sounds.
0
2
4
6
8
10
12
Expe_2 Control_2 Expe_3 Control_3
Pre Post
Figure 4.
Mean of non-produced phonemes in the pretest and post-test depending on the severity of
articulation difficulties (moderate difficulties: 2; severe difficulties: 3).
Int. J. Environ. Res. Public Health 2022, 19, x FOR PEER REVIEW 10 of 13
Figure 5. Mean of pre- and post-test non-produced sounds for the experimental and control groups.
4. Discussion
The aim of this study was to analyze the efficiency of nonverbal oro-motor exercises
for the articulation of sounds in speech development. Because they are generally used in
professional practice, as mentioned in the Introduction and in the evidence-based practice
model, it was useful to know if they are the most appropriate kind of intervention to un-
dertake. The results showed no significant differences between experimental and control
groups when nonverbal oro-motor exercises were used in children with typical develop-
ment and non-produced sounds. After three months of intervention, both groups im-
proved in their production of sounds, considering the number of phonemes in their
speech in the pretest and post-test phases. Thus, our results indicated that these exercises
are not useful for the acquisition of sounds in typical speech development. Nevertheless,
it should be noted that for children with organic deficiencies (such as dysglossia) or for
neurological disorders (e.g., dysarthria), they could be useful, as, in these pathologies,
there are usually deficiencies in the phonoarticulatory organs, and studies in those cases
pointed to an improvement with oro-motor movements [55,56].
We also attempted to clarify whether nonverbal oro-motor exercises would be more
efficient for some phonemes, considering that our intervention was general and non-spe-
cific for non-produced sounds in the child’s repertoire. Despite having made an exhaus-
tive, wide statistical analysis, analyzing phoneme by phoneme first (or by consonant
groups), as well as grouping them in reference to several criteria (alveolar, fricative, all
consonant groups with /l/ and with /r/, etc.) we did not find significant differences be-
tween the group that received the intervention program and the one that did not. There
were differences regarding the severity of the problem: i.e., participants who had a more
severe deficit (more than seven non-produced sounds) improved more than those with
moderate ones (between two and six non-produced sounds), but these results were not
due to intervention with the verbal oro-motor exercises as children in both groups im-
proved in the same way.
0
1
2
3
4
5
6
7
Pre Post
Experimental Control
Figure 5.
Mean of pre- and post-test non-produced sounds for the experimental and control groups.
4. Discussion
The aim of this study was to analyze the efficiency of nonverbal oro-motor exercises
for the articulation of sounds in speech development. Because they are generally used
in professional practice, as mentioned in the Introduction and in the evidence-based
practice model, it was useful to know if they are the most appropriate kind of intervention
to undertake. The results showed no significant differences between experimental and
control groups when nonverbal oro-motor exercises were used in children with typical

Int. J. Environ. Res. Public Health 2022,19, 5459 10 of 13
development and non-produced sounds. After three months of intervention, both groups
improved in their production of sounds, considering the number of phonemes in their
speech in the pretest and post-test phases. Thus, our results indicated that these exercises
are not useful for the acquisition of sounds in typical speech development. Nevertheless,
it should be noted that for children with organic deficiencies (such as dysglossia) or for
neurological disorders (e.g., dysarthria), they could be useful, as, in these pathologies, there
are usually deficiencies in the phonoarticulatory organs, and studies in those cases pointed
to an improvement with oro-motor movements [55,56].
We also attempted to clarify whether nonverbal oro-motor exercises would be more
efficient for some phonemes, considering that our intervention was general and non-specific
for non-produced sounds in the child’s repertoire. Despite having made an exhaustive, wide
statistical analysis, analyzing phoneme by phoneme first (or by consonant groups), as well
as grouping them in reference to several criteria (alveolar, fricative, all consonant groups
with /l/ and with /r/, etc.) we did not find significant differences between the group
that received the intervention program and the one that did not. There were differences
regarding the severity of the problem: i.e., participants who had a more severe deficit (more
than seven non-produced sounds) improved more than those with moderate ones (between
two and six non-produced sounds), but these results were not due to intervention with the
verbal oro-motor exercises as children in both groups improved in the same way.
Doubts about efficiency in this kind of intervention are based on the open debate
that has lasted for over a decade between defenders of nonverbal oro-motor exercises for
phonetic disorders (e.g., [
12
,
15
,
36
,
37
,
54
]) and authors who claim that this type of treatment
is not efficient in children with typical language development (e.g., [40–43,47,57]).
In this study, as in others carried out in the English-speaking context, evidence sup-
ported the claim that nonverbal oro-motor exercises do not improve the articulation of
sounds in children with typical development [
13
]. According to these authors, movements
to produce speech are different from isolated movements of articulatory organs, and hence,
there is no evidence to support the idea that these movements will improve language
development. Indeed, some authors claimed that motor action neural circuits used for
muscular activities or isolated movements of structures that participate in speech, such as
the soft palate, tongue, or lips, are different from those that produce speech [
58
]. Thus, for
instance, the movement of lifting the tongue inside the mouth and touching the palate is
not the same movement as that which produces the phoneme /t/.
In addition, from the phonological perspective, it is assumed that phonemes are not
static but vary depending on their position in the word [
31
]. Hence, both articulation
and audition influence the child’s language development, enabling coarticulation. Thus,
syllables, and not phonemes, should be considered, as well as their order in the word
when analyzing phonological disorders. These are usually understood as simplification
phonological processes [
13
]. From this perspective, auditory discrimination is considered
one of the main causes of speech disorders, and it was proposed that phonemes are
contrasted with other phonemes (minimum pairs) to improve phonetic–phonological
difficulties [
2
,
11
,
30
]. It is also possible that the intervention carried out was not the most
adequate for phoneme acquisition. Some authors have claimed that nonverbal oro-motor
exercises should be specifically adjusted for each phoneme [
54
,
59
] and not used for a wide
number. It should also be considered that a 3-month intervention might not be long enough
for relevant improvements.
More empirical evidence is needed to evaluate the specific efficiency of nonverbal
oro-motor exercises compared to other intervention methods such as blowing, auditory
discrimination, syllable, word repetition, etc. [
15
]. Equally, some interventions in speech
therapy are based more on tradition than on scientific foundation and should be reconsid-
ered, as well as books that recommend the use of non-verbal oro-motor movement exercises
for articulatory disorders without the necessary empirical evidence on their efficiency. Our
study plays a notable preventive role, as nonverbal oro-motor exercises are widely used in

Int. J. Environ. Res. Public Health 2022,19, 5459 11 of 13
preschool centers to prevent speech difficulties (see, for example, [
48
]), but this practice
should be questioned in accordance with accumulative experimental evidence on the topic.
Author Contributions: Conceptualization, P.P.-L. and M.O.-S.; methodology, A.V.V.-G. and M.O.-S.;
formal analysis, A.V.V.-G.; investigation, P.P.-L. and M.O.-S.; writing—original draft preparation,
P.P.-L.; writing—review and editing, M.O.-S.; supervision, P.P.-L. and A.V.V.-G. All authors have read
and agreed to the published version of the manuscript.
Funding: This research received no external funding.
Institutional Review Board Statement:
This study was conducted according to the guidelines of the
Declaration of Helsinki and approved by the Institutional Review Board (or Ethics Committee) of the
University of Murcia (3 August 2021).
Informed Consent Statement:
Informed consent was obtained from all subjects involved in the study.
Data Availability Statement:
The data presented in this study are available on request from the
corresponding author.
Conflicts of Interest: The authors declare no conflict of interest.
References
1.
American Psychiatry Association. DSM-5. Manual Diagnóstico y Estadístico de los Trastornos Mentales;
Editorial Médica Panamericana
:
Madrid, Spain, 2013.
2.
Cervera-Mérida, J.F.; Ygual-Fernández, A. Intervención logopédica en los trastornos fonológicos desde el paradigma psicol-
ingüístico del procesamiento del habla. Rev. Neurol. 2003,36, 39–53. [CrossRef]
3. Hidalgo, A.; Quilis, M. La voz del Lenguaje: Fonética y Fonología del Español; Prosopopeya: Valencia, Spain, 2012.
4. De las Heras, G.; Rodríguez, L. Guía de Intervención Logopédica en las Dislalias; Editorial Síntesis: Madrid, Spain, 2015.
5.
Namasivayam, A.K.; Pukonen, M.; Goshulk, D.; Yu, V.Y.; Kadis, D.S.; Kroll, R.; Pang, E.W.; De Nilc, L.F. Relationship between
speech motor control and speech intelligibility in children with speech sound disorders. J. Commun. Disord.
2013
,46, 264–280.
[CrossRef] [PubMed]
6. Pascual, P. La Dislalia. Naturaleza, Diagnóstico y Rehabilitación; CEPE: Madrid, Spain, 2007.
7.
Campos, A.D.; Campos, L.D. Patologías de la comunicación. Proyecto docente para enfermería infantil. Dislalias. Rev. Enfermería
Glob. 2014,34, 444–452. [CrossRef]
8.
Ygual-Fernández, A.; Cervera-Mérida, J.F.; Rosso, P. Utilidad del análisis fonológico en la terapia del lenguaje. Rev. De Neurol.
2008,46, 97–100. [CrossRef]
9.
Bosch, L. Trastornos del desarrollo fonético y fonológico. In Manual de Desarrollo y Alteraciones del Lenguaje. Aspectos Evolutivos y
Patología en el niño y en el Adulto; Puyuelo, M., Rondal, J.A., Eds.; Masson: Barcelona, Spain, 2003; pp. 189–204.
10.
Juárez, A.; Monfort, M. Estimulación del Lenguaje Oral. Un Modelo Interactivo para niños con Necesidades Educativas Especiales; Entha
Ediciones: Madrid, Spain, 2001.
11.
Aguado, G. Trastorno de habla y articulación. In Trastornos del Habla y de la voz; Coll-Florit, M., Aguado, G., Fernández-Zuñiga, A.,
Gambra, S., Perelló, E., Vila-Rovira, J.M., Eds.; Editorial UOC: Barcelona, Spain, 2013; pp. 13–63.
12.
Toja, N.; Peña-Casanova, J. Dislalias. In Manual de Logopedia; Peña-Casanova, J., Ed.; Elsevier Masson: Barcelona, Spain, 2014;
pp. 139–149.
13.
Susanibar, F.; Dioses, A.; Tordera, J.C. Principios para la evaluación e intervención de los trastornos de los sonidos del habla—
TSH. In Trastornos del Habla. De los Fundamentos a la Evaluación; Susanibar, F., Dioses, A., Marchesan, I., Guzmán, M., Leal, G.,
Bohnen, A.J., Eds.; Editorial EOS: Madrid, Spain, 2016; pp. 47–124.
14. Barrios, P.M. Cómo lograr el aprendizaje en alumnos con dificultades fonéticas y fonológicas. Rev. Encuentro Educ. 2010,6, 4–8.
15.
Gallego, J.L.; Gómez, I.A.; Ayllón, M.F. Trastornos fonológicos en niños: Resultados de la aplicación de un programa. Rev. Investig.
Educ. 2015,33, 453–470. [CrossRef]
16.
Macrae, T.; Tyler, A.A. Speech abilities in preschool children with speech sound disorder with and without co-ocurring language
impairment. Lang. Speech Hear. Serv. Sch. 2014,45, 302–313. [CrossRef]
17.
Chevrie-Muller, C. Semiología de los trastornos del lenguaje en el niño. In El Lenguaje del niño. Desarrollo Normal, Evaluación y
Trastornos; Narbona, J., Chevrie-Muller, C., Eds.; Masson: Barcelona, Spain, 1997; pp. 189–194.
18.
Preston, J.L.; Hull, M.; Edwards, M.L. Preschool speech error patterns predict articulation and phonological awareness outcomes
in children with histories of speech sound disorders. Am. J. Speech-Lang. Pathol. 2013,22, 173–184. [CrossRef]
19. Dodd, B. Differential diagnosis of pediatric speech sound disorder. Curr. Dev. Disord. Rep. 2014,1, 189–196. [CrossRef]
20. Moreno, R.; Ramírez, M.A. Las habitaciones de la dislalia. Rev. Electrónica Investig. Docencia Creat. 2012,1, 38–45.
21.
Conde-Guzón, P.A.; Quirós-Expósito, P.; Conde-Guzón, M.J.; Bartolomé-Albistegui, M. Perfil neuropsicológico de niños con
dislalias: Alteraciones mnésicas y atencionales. An. Psicol. 2014,30, 1105–1114. [CrossRef]
22. Dodd, B. Differential Diagnosis and Treatment of Children with Speech Disorder; John Wiley & Sons: Hoboken, NJ, USA, 2013.

Int. J. Environ. Res. Public Health 2022,19, 5459 12 of 13
23.
Duffy, J.R. Motor Speech Disorders E-Book: Substrates, Differential Diagnosis, and Management; Elsevier Health Sciences: Amsterdam,
The Netherlands, 2019.
24.
Galiana, J.; González, G.; Sauca, A. Intervención y tratamiento en las dislalias con la ayuda del programa de visualización del
habla MetaVox. Innovaeduca Net 2004,3, 42–50.
25.
Gallego, J.L.; Rodríguez, A. Atención Logopédica al Alumnado con Dificultades en el Lenguaje Oral; Ediciones Aljibe: Málaga,
Spain, 2005.
26.
Hassan, E.S.; Darweesh, A.E.D.M.; Ibrahim, R.A.; Zareh, W.M. Psychological status of school-aged children and adolescents with
dyslalia. J. Curr. Med. Res. Pract. 2020,5, 217.
27.
Moreno, J.M.; Mateos, M.R. Estudio sobre la interrelación entre la dislalia y la personalidad del niño. Rev. Electrónica Investig.
Psicológica 2005,7, 133–150. [CrossRef]
28.
Namasivayam, A.K.; Coleman, D.; O’Dwyer, A.; van Lieshout, P. Speech Sound Disorders in children: An articulatory phonology
perspective. Front. Psychol. 2020,10, 2998. [CrossRef] [PubMed]
29. Browman, C.P.; Goldstein, L. Articulatory phonology: An overview. Phonetica 1992,49, 115–180. [CrossRef] [PubMed]
30.
Acosta, V.M.; Moreno, A.M. Dificultades del Lenguaje en Ambientes Educativos. Del Retraso al Trastorno Específico del Lenguaje; Masson:
Barcelona, Spain, 2001.
31. Villegas, F. Manual de Logopedia. Evaluación e Intervención de las Dificultades Fonológicas; Pirámide: Madrid, Spain, 2010.
32.
Bernthal, J.E.; Bankson, N.W.; Flipsen, P. Articulation and Phonological Disorders: Speech Sound Disorders in Children, 8th ed.; Pearson:
Boston, MA, USA, 2016.
33.
Peña-Brooks, A.; Hegde, M.N. Assessment and Treatment of Articulation and Phonological Disorders in Children; Pro-Ed: Austin, TX,
USA, 2015.
34. Bosch, L. Evaluación Fonológica del Habla Infantil; Elsevier Masson: Barcelona, Spain, 2004.
35.
Busto, M.C.; Faig, V.; Rafanell, L.; Madrid, L.; Martínez, P. Valoración del habla en niños de educación infantil y primaria. Phonica
2008,4, 3–35.
36.
Bahr, D. The oral motor debate: Where do we go from here? In Proceedings of the American Speech-Language-Hearing
Association Convention, Chicago, IL, USA, 15–17 November 2008.
37.
Bahr, D.; Rosenfeld-Johnson, S. Treatment of children with Speech Oral Placement Disorders (OPDs): A paradigm emerges.
Commun. Disord. Q. 2010,20, 108. [CrossRef]
38.
Kamal, S.M. The use of oral motor exercises among speech language pathologists in Jordan. J. Lang. Teach. Res.
2021
,12, 99–103.
[CrossRef]
39.
Marshalla, P. The Roots of Oral-Motor Therapy: A Personal View. 2011. Available online: https://pammarshalla.com/the-roots-
of-oral-motortherapy-a-personal-view/ (accessed on 5 May 2021).
40.
Bowen, C. What is the evidence for oral motor therapy? Acquiring knowledge in speech, language and hearing. Speech Pathol.
Aust. 2005,7, 144–147.
41.
Lof, G.L. Reasons why non-speech oral motor exercises should not be used for speech sound disorders. In Proceedings of the
American Speech-Language-Hearing Association Convention, Boston, MA, USA, 24–26 November 2007.
42.
Lof, G.L. Non-speech oral motor exercises: An update on the controversy. In Proceedings of the American Speech-Language-
Hearing Association Convention, New Orleans, LA, USA, 19–21 November 2009.
43.
Lof, G.L.; Watson, M. A nationwide survey of non-speech oral motor exercise use: Implications for evidence-based practice. Lang.
Speech Hear. Serv. Sch. 2008,39, 392–407. [CrossRef]
44.
Merkel-Walsh, R.; Rosenfeld-Johnson, S. Oral placement therapy (OPT) versus Non-Speech Oral Motor Exercises (NSOME):
Understanding the debate. In Proceedings of the American Speech-Language-Hearing Association Convention, Denver, CO,
USA, 12–14 November 2015.
45.
Furlong, L.M.; Morris, M.E.; Serry, T.A.; Erickson, S. Treating childhood speech sound disorders: Current approaches to
management by Australian speech-language pathologists. Lang. Speech Hear. Serv. Sch. 2021,52, 581–596. [CrossRef] [PubMed]
46.
Watson, M.M.; Lof, G.L. A survey of university professors teaching speech sound disorders: Nonspeech oral motor exercises and
other topics. Lang. Speech Hear. Serv. Sch. 2009,40, 256–270. [CrossRef]
47.
Ygual-Fernández, A.; Cervera-Mérida, J.F. Eficacia de los programas de ejercicios de motricidad oral para el tratamiento
logopédico de las dificultades del habla. Rev. Neurol. 2016,62, S59–S64. [PubMed]
48.
Azpitarte, N. Programa para la prevención de las dislalias en educación infantil. Hada de los cuentos. Educ. Futuro
2008
,
18, 177–200.
49.
González, M.J. Dificultades en la articulación: Trastornos fonológicos y fonéticos. In Enciclopedia Temática de Logopedia;
Gallego, J.L., Ed.; Aljibe: Málaga, Spain, 2006; pp. 87–108.
50. Monfort, M.; Juárez, A. Registro Fonológico Inducido; CEPE: Madrid, Spain, 2006.
51.
Cervera-Mérida, J.F.; Ygual-Fernández, A. Metodología para la intervención logopédica en los trastornos del habla. Rev. De Logop.
Fonología Y Audiol. 1994,14, 19–26. [CrossRef]
52.
Parra, P.; Olmos, M.; Cabello, F.; Valero-García, A.V. Eficacia del entrenamiento en praxias fonoarticulatorias en los trastornos de
los sonidos del habla en niños de 4 años. Rev. Logop. Foniatría Audiol. 2016,36, 77–84. [CrossRef]
53.
Schrager, O.L.; O
´
Donnell, C.M. Actos motores oro-faringo-faciales y praxias fonoarticulatorias. Fonoaudiol. Asoc. Argent. Logop.
Foniatría Audiol. 2001,47, 22–32.

Int. J. Environ. Res. Public Health 2022,19, 5459 13 of 13
54. Seivane, M.P. Cicerón. Programa para la Adquisición y Desarrollo de la Capacidad Articulatoria; CEPE: Madrid, Spain, 2007.
55.
Bartuilli, M.; Cabrera, P.J.; Periñan, M.C. Guía Técnica de Intervención Logopédica. Terapia Miofuncional; Editorial Síntesis: Madrid,
Spain, 2010.
56. Melle, N. Guía de Intervención Logopédica en la Disartria; Editorial Síntesis: Madrid, Spain, 2008.
57. Clark, H.M. Clinical decision making and oral motor treatments. ASHA Lead. 2005,10, 8–35. [CrossRef]
58.
Kent, R.D. Nonspeech Oral Movements and Oral Motor Disorders: A Narrative Review. Am. J. Speech-Lang. Pathol.
2015
,
24, 763–789. [CrossRef]
59. Vallés, A. Fichas de Recuperación de las Dislalias; CEPE: Madrid, Spain, 2008.