Georgia Zellou

Georgia Zellou
University of California, Davis | UCD · Department of Linguistics

PhD

About

63
Publications
10,052
Reads
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404
Citations
Additional affiliations
July 2014 - present
University of California, Davis
Position
  • Professor (Assistant)
July 2012 - June 2014
University of Pennsylvania
Position
  • PostDoc Position

Publications

Publications (63)
Article
We investigated phonetic imitation of coarticulatory vowel nasality using an adapted shadowing paradigm in which participants produced a printed word (target) after hearing a different word (prime). Two versions of primes with nasal codas were used: primes with a natural degree of vowel nasality and hypernasalised primes. The version of the prime p...
Article
The current study investigates correlations between individual differences in the production of nasal coarticulation and patterns of perceptual compensation in American English. A production study (Experiment 1) assessed participants' nasal coarticulation repertoires by eliciting productions of CVC, CVN and NVN words. Stimuli for two perception tas...
Article
This study investigates the spontaneous phonetic imitation of coarticulatory vowel nasalization. Speakers produced monosyllabic words with a vowel-nasal sequence either from dense or sparse pho-nological neighborhoods in shadowing and word-naming tasks. During shadowing, they were exposed to target words that were modified to have either an artific...
Article
Full-text available
Words produced to infants exhibit phonetic modifications relative to speech to adult interlocutors, such as longer, more canonical segments and prosodic enhancement. Meanwhile, within speech directed towards adults, pho-netic variation is conditioned by word properties: lower word frequency and higher phonological neighborhood density (ND) correlat...
Article
This study examines change over time in coarticulatory vowel nasality in both real and apparent time in Philadelphia English. We measure nasal-adjacent vowels in words from a corpus of conversational speech and find systematic, community-level changes in degree of nasal coarticulation over time in Philadelphia. Specifically, in all speakers who wer...
Book
There is debate about how coarticulation is represented in speakers' mental grammar, as well as the role that coarticulation plays in explaining synchronic and diachronic sound patterns across languages. This Element takes an individual-differences approach in examining nasal coarticulation in production and perception in order to understand how co...
Article
How sound change is initiated and propagates in smaller speech communities is not well understood. This paper provides an overview of the main themes, including theoretical and methodological issues, of the special collection on sound change in endangered and small speech communities.
Article
Full-text available
The current study investigates the intelligibility of face-masked speech while manipulating speaking style, presence of visual information about the speaker, and level of background noise. Speakers produced sentences while in both face-masked and non-face-masked conditions in clear and casual speaking styles. Two online experiments presented the se...
Article
This study examined how speaking style and guise influence the intelligibility of text-to-speech (TTS) and naturally produced human voices. Results showed that TTS voices were less intelligible overall. Although using a clear speech style improved intelligibility for both human and TTS voices (using “newscaster” neural TTS), the clear speech effect...
Article
Full-text available
Millions of people engage in spoken interactions with voice activated artificially intelligent (voice-AI) systems in their everyday lives. This study explores whether speakers have a voice-AI-specific register, relative to their speech toward an adult human. Furthermore, this study tests if speakers have targeted error correction strategies for voi...
Article
Some models of speech production propose that speech variation reflects an adaptive trade-off between the needs of the listener and constraints on the speaker. The current study considers communicative load as both a situational and lexical variable that influences phonetic variation in speech to real interlocutors. The current study investigates w...
Article
The current study investigates phonetic imitation of multiple acoustic features of pre-nasal /æ/ in California English. There is a great deal of cross-speaker heterogeneity: Many speakers show a raised /æN/ variant, in tandem with a backing and lowering of /æC/ (i.e., “split” short-a nasal system). This innovative split can also be realized with en...
Article
Full-text available
This study tests whether individuals vocally align toward emotionally expressive prosody produced by two types of interlocutors: a human and a voice-activated artificially intelligent (voice-AI) assistant. Participants completed a word shadowing experiment of interjections (e.g., “Awesome”) produced in emotionally neutral and expressive prosodies b...
Article
No PDF available ABSTRACT Facing linguistic barriers to communication, talkers spontaneously adjust their speech, facilitating perception by their listener. These adjustments characteristically involve hyperarticulation, such as reduced speech rate, increased vowel dispersion, and increased segmental duration. Listener-based hyperarticulation could...
Conference Paper
Full-text available
The current study explores whether perception of coarticulatory vowel nasalization differs by speaker age (adult vs. child) and type of voice (naturally produced vs. synthetic speech). Listeners completed a 4IAX discrimination task between pairs containing acoustically identical (both nasal or oral) vowels and acoustically distinct (one oral, one n...
Article
Full-text available
The current study tests whether individuals (n = 53) produce distinct speech adaptations during pre-scripted spoken interactions with a voice-AI assistant (Amazon’s Alexa) relative to those with a human interlocutor. Interactions crossed intelligibility pressures (staged word misrecognitions) and emotionality (hyper-expressive interjections) as con...
Article
Two studies investigated the influence of conversational role on phonetic imitation toward human and voice-AI interlocutors. In a Word List Task, the giver instructed the receiver on which of two lists to place a word; this dialogue task is similar to simple spoken interactions users have with voice-AI systems. In a Map Task, participants completed...
Article
Full-text available
This study investigates the impact of wearing a fabric face mask on speech comprehension, an underexplored topic that can inform theories of speech production. Speakers produced sentences in three speech styles (casual, clear, positive-emotional) while in both face-masked and non-face-masked conditions. Listeners were most accurate at word identifi...
Article
Full-text available
This paper investigates users’ speech rate adjustments during conversations with an Amazon Alexa socialbot in response to situational (in-lab vs. at-home) and communicative (ASR comprehension errors) factors. We collected user interaction studies and measured speech rate at each turn in the conversation and in baseline productions (collected prior...
Article
This study investigates the perception of coarticulatory vowel nasality generated using different text-to-speech (TTS) methods in American English. Experiment 1 compared concatenative and neural TTS using a 4IAX task, where listeners discriminated between a word pair containing either both oral or nasalized vowels and a word pair containing one ora...
Article
Full-text available
Speech alignment is where talkers subconsciously adopt the speech and language patterns of their interlocutor. Nowadays, people of all ages are speaking with voice-activated, artificially-intelligent (voice-AI) digital assistants through phones or smart speakers. This study examines participants’ age (older adults, 53–81 years old vs. younger adult...
Conference Paper
Full-text available
A production study explored the acoustic characteristics of /ae/ in CVC and CVN words spoken by California speakers who raise /ae/ in pre-nasal contexts. Results reveal that the phonetic realization of the /ae/-/ɛ/ contrast in these contexts is multidimensional. Raised pre-nasal /ae/ is close in formant space to /ɛ/, particularly over the second ha...
Conference Paper
Full-text available
This study tests speech-in-noise perception and social ratings of speech produced by different text-to-speech (TTS) synthesis methods. We used identical speaker training datasets for a set of 4 voices (using AWS Polly TTS), generated using neural and concatenative TTS. In Experiment 1, listeners identified target words in semantically predictable a...
Conference Paper
Full-text available
The present study compares how individuals perceive gradient acoustic realizations of emotion produced by a human voice versus an Amazon Alexa text-to-speech (TTS) voice. We manipulated semantically neutral sentences spoken by both talkers with identical emotional synthesis methods, using three levels of increasing 'happiness' (0 %, 33 %, 66 % 'hap...
Conference Paper
Full-text available
Increasingly, people are having conversational interactions with voice-AI systems, such as Amazon's Alexa. Do the same social and functional pressures that mediate alignment toward human interlocutors also predict align patterns toward voice-AI? We designed an interactive dialogue task to investigate this question. Each trial consisted of scripted,...
Conference Paper
Full-text available
More and more, humans are engaging with voice-activated artificially intelligent (voice-AI) systems that have names (e.g., Alexa), apparent genders, and even emotional expression; they are in many ways a growing 'social' presence. But to what extent do people display sociolinguistic attitudes, developed from human-human interaction, toward these di...
Conference Paper
Full-text available
The current study tests subjects' vocal alignment toward female and male text-to-speech (TTS) voices presented via three systems: Amazon Echo, Nao, and Furhat. These systems vary in their physical form, ranging from a cylindrical speaker (Echo), to a small robot (Nao), to a human-like robot bust (Furhat). We test whether this cline of personificati...
Conference Paper
Full-text available
Humans are now regularly speaking to voice-activated artificially intelligent (voice-AI) assistants. Yet, our understanding of the cognitive mechanisms at play during speech interactions with a voice-AI, relative to a real human, interlocutor is an understudied area of research. The present study tests whether top-down guise of "apparent humanness"...
Conference Paper
Full-text available
The current study explores whether the top-down influence of speaker age guise influences patterns of compensation for coarticulation. /u/-fronting variation in California is linked to both phonetic and social factors: /u/ in alveolar contexts is fronter than in bilabial contexts and /u/-fronting is more advanced in younger speakers. We investigate...
Preprint
Full-text available
In this study, we test two questions of how users perceive neural vs. concatenative text-to-speech (TTS): 1) does the TTS method influence speech intelligibility in adverse listening conditions? and 2) does a user’s ratings of the voice’s social attributes shape intelligibility? We used identical speaker training datasets for a set of 4 speakers (u...
Article
Full-text available
Listeners show better-than-chance discrimination of nasalized and oral vowels occurring in appropriate consonantal contexts. Yet, the methods for investigating partial perceptual compensation for nasal coarticulation often include nasal and oral vowels containing naturally different pitch contours. Listeners may therefore be discriminating between...
Article
While the fact that phonetic information is evaluated in a non-discrete, probabilistic fashion is well established, there is less consensus regarding how long such encoding is maintained. Here, we examined whether people maintain in memory the amount of vowel nasality present in a word when processing a subsequent word that holds a semantic depende...
Conference Paper
Full-text available
The current study explores the extent to which humans vocally align to digital device voices (i.e., Apple's Siri) and human voices. First, participants shadowed word productions by 4 model talkers: a female and a male digital device voice, and a female and a male real human voice. Second, an independent group of raters completed an AXB task assessi...
Conference Paper
Full-text available
We examined the phonetic realization of oral and pre-nasal /ae/ in speakers from three distinct sub-regions of California: Southern California, the Bay Area, and the Central Valley. Four acoustic variables were measured: two midpoint formant values (F1, F2), diphthongization, and acoustic nasality. Results show that speakers from the sub-regions ex...
Article
Vowels are enhanced via vowel-space expansion in perceptually difficult contexts, including in words subject to greater lexical competition. Yet, vowel hyperarticulation often covaries with other acoustic adjustments, such as increased nasal coarticulation, suggesting that the goals of phonetic enhancement are not strictly to produce canonical phon...
Article
Individual variation is ubiquitous and empirically observable in most phonological behaviors, yet relatively few studies aim to capture the heterogeneity of language processing among individuals, as opposed to those focusing primarily on group-level patterns. The study of individual differences can shed light on the nature of the cognitive represen...
Article
Full-text available
Coarticulation makes vowels in context acoustically different from context-free vowels. Listeners sometimes compensate by ascribing these acoustic effects to their source, but the conditions under which they do so have not yet been fully pinpointed. Ohala (1993) had suggested that acoustic effects which are temporally more distant from their source...
Preprint
The poetry reading has, for decades, been an unavoidable aspect of the professional poet's life. And the institutionalization of creative writing, government sponsorship of the arts, access to audio and video recording technologies, and the digitization of audio recordings, have accelerated the number of poetry readings and provided scholars with g...
Article
Surface-level phonetic details are used during word recognition. Yet, questions remain about how these details are encoded in lexical representations and the role of memory and attention during this process. The current study utilizes lexical repetition priming to examine the effect of a delay between hearing a word repeated with either the same or...
Article
This study investigates the spontaneous phonetic imitation of coarticulatory vowel nasalization. Speakers produced monosyllabic words with a vowel-nasal sequence either from dense or sparse phonological neighborhoods in shadowing and word-naming tasks. During shadowing, they were exposed to target words that were modified to have either an artifici...
Article
Short-a, or /æ/, production varies substantially across American English dialects and is noted to be useful in describing regional pronunciation differences. The current study examines the production and perception of /æ/ in California English, which raises in words with a final nasal coda (both velar and non-velar nasals). We explore both the acou...
Article
Full-text available
Lakota (Siouan) has both contrastive and coarticulatory vowel nasality, and both nasal and oral vowels can occur before or after a nasal consonant. This study examines the timing and degree patterns of acoustic vowel nasality across contrastive and coarticulatory contexts in Lakota, based on data from six Lakota native speakers. There is clear evid...
Conference Paper
Full-text available
Listeners are quicker responding to a word the second time it is heard, but this effect is reduced when the word is repeated by a different speaker. Is this reduction related to the auditory dissimilarity between different voices, or does it result from top-down effects associated with perceived speaker changes? To investigate this, listeners were...
Conference Paper
Full-text available
We use acoustic measurements from spontaneous corpora data to compare the social conditioning of nasal coarticulation across two American English dialects: Mid-Atlantic (Philadelphia Neighborhood Corpus) and Midlands (Buckeye Corpus). Each dialect is represented by 40 speakers stratified by age and sex. An acoustic measure of nasal coarticulation i...
Article
This study examines the influences of abstract and episodic representations of words in auditory repetition priming. Two manipulations of prime and target items were employed, token-change and voice-change. First, either the target item consisted of a different token spoken by the same speaker as the prime (token-change), or the target item was a t...
Article
Full-text available
Nasality encodes a phonemic consonant contrast in English, and its acoustic correlates affect adjacent vowels. The phonological status of nasality predicts that people encode vowel nasality as a discrete and binary feature, i.e., as the presence or absence of velum lowering. The present study examined whether listeners can also infer the degree of...
Article
Full-text available
Speech produced in the context of real or imagined communicative difficulties is characterized by hyperarticulation. Phonological neighborhood density (ND) conditions similar patterns in production: Words with many neighbors are hyperarticulated relative to words with fewer; Hi ND words also show greater coarticulation than Lo ND words [e.g., Scarb...
Article
Full-text available
This study investigates the imitability of contextual vowel nasalization in English. Unlike other phonetic features reported to be imitable [e.g., vowel formants (Babel, 2012), VOT (Nielsen, 2011)], vowel nasality is non-contrastive in English. Nasality is, however, systematically variable: words from dense lexical neighborhoods (high-ND words) are...
Article
Moroccan Arabic (MA) displays a synchronic consonant harmony alternation where underlying alveolar sibilants can assimilate in place of articulation to a following palatal sibilant, e.g., seƷera ~ ʃeƷera "tree". This study investigates the phonetic realization of the assimilated sibilant variant in consonant harmony forms. This consonant harmony pr...
Conference Paper
Full-text available
This study investigates the acoustic and perceptual consequences of nasal coarticulation in American English. Nasalized (coarticulated) vowels were found to be closer in the F1-F2 acoustic vowel space than corresponding oral (non-coarticulated) vowels, indicating that contrast is reduced in the nasal vowel space, relative to the oral vowel space. W...
Conference Paper
Full-text available
This aerodynamic study investigates velum activity during the production of nasal and pharyngeal consonants, using airflow, and during the production of vowels adjacent to nasal and pharyngeal consonants, using airflow and nasalance, in Moroccan Arabic (MA). The results indicate that the velum is lowered during the production of pharyngeals and tha...
Conference Paper
Full-text available
This study investigates the effect of contrastive stress on nasal coarticulation in English. There are two opposing findings about the correlation between coarticulation and hyperarticulation in the literature: first, that emphasis results in timing patterns which reduce coarticulation; second, that both increased hyperarticulation and increased co...
Article
Full-text available
Moroccan Arabic (MA) has a derivational noun circumfix /ta-...-t/ that is borrowed from the neighboring Berber languages. This circumfix is highly productive on native MA noun stems but not productive on borrowed Berber stems (which are rare in MA). This pattern of productivity is taken to be evidence in support of direct borrowing of morphology (c...
Article
This paper quantitatively tests the prediction that loanword adaptation occurs in bilinguals who must resolve two competing requirements: an accurate mental representation of the word from the source language and the phonological requirements of the receiving language. The prediction is that this duel requirement would result in the phonetic qualit...
Article
Studies of the perception of vowel nasality often use synthesized stimuli to produce controlled gradience in nasality. To investigate the perception of nasality in natural speech, a method was developed wherein vowels differing naturally in nasality (e.g., from CVC and NVN words) are mixed to yield tokens with various degrees of nasality. First, mo...
Article
Pharyngeal consonants have been shown cross-linguistically to be co-articulated with velopharyngeal port opening (Bladon and Al-Bamerni, 1982, Elgendy, 2001). We examined whether coarticulatory vowel nasality is a perceptual cue to an adjacent pharyngeal, and/or nasal, consonant in Moroccan Arabic (MA). Monosyllabic MA words spoken by a native spea...
Article
Full-text available
Nasal coarticulation has been shown to vary systematically in words depending on the number of phonological neighbors: words with many neighbors are produced with a greater degree of vowel nasality than words with fewer phonological neighbors [9]. This study examines the effect of this systematic low-level variation on lexical perception. The degre...

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