Cristian Tejedor-García

Radboud University | RU · Centre for Language Studies

Over the last few years, we have witnessed a growing interest in computer-assisted pronunciation training (CAPT) tools and the commercial success of foreign language teaching applications that incorporate speech synthesis and automatic speech recognition technologies. However, empirical evidence supporting the pedagogical effectiveness of these sys...

Learning games have a remarkable potential for education. They provide an emergent form of social participation that deserves the assessment of their usefulness and efficiency in learning processes. This study describes a novel learning game for foreign pronunciation training in which players can challenge each other. Native Spanish speakers perfor...

This study addresses the issue of automatic pronunciation assessment (APA) and its contribution to the teaching of second language (L2) pronunciation. Several attempts have been made at designing such systems, and some have proven operationally successful. However, the automatic assessment of the pronunciation of short words in segmental approaches...

Parkinson's disease (PD), the second most prevalent neurodegenerative disorder worldwide, frequently presents with early-stage speech impairments. Recent advancements in Artificial Intelligence (AI), particularly deep learning (DL), have significantly enhanced PD diagnosis through the analysis of speech data. Nevertheless, the progress of research...

Alzheimer's Disease (AD) is the world's leading neurodegenerative disease, which often results in communication difficulties. Analysing speech can serve as a diagnostic tool for identifying the condition. The recent ADReSS challenge provided a dataset for AD classification and highlighted the utility of manual transcriptions. In this study, we used...

Recent advancements in large pretrained Automatic Speech Recognition (ASR) systems have opened new avenues for digital education applications, such as reading diagnosis in primary schools. Leveraging ASR in this context can enhance teachers' ability to assess students' reading skills efficiently while offering students interactive reading exercises...

Computer-Assisted Pronunciation Training (CAPT) for non-native children leverages speech technology to aid in improving pronunciation accuracy. Hybrid automatic speech recognition (ASR) models, combining neural networks with statistical methods, are well-suited for CAPT due to their high accuracy and reduced latency, especially in limited search sp...

Speech recordings are being more frequently used to detect and monitor disease, leading to privacy concerns. Beyond cryptography, protection of speech can be addressed by approaches, such as perturbation, disentanglement, and re-synthesis, that eliminate sensitive information of the speaker, leaving the information necessary for medical analysis pu...

Speech recordings are being more frequently used to detect and monitor disease, leading to privacy concerns. Beyond cryptography, protection of speech can be addressed by approaches, such as perturbation, disentanglement, and re-synthesis, that eliminate sensitive information of the speaker, leaving the information necessary for medical analysis pu...

Automatic reading diagnosis systems can benefit both teachers for more efficient scoring of reading exercises and students for accessing reading exercises with feedback more easily. However, there are limited studies on Automatic Speech Recognition (ASR) for child speech in languages other than English, and limited research on ASR-based reading dia...

Parkinson’s disease (PD), the second most prevalent neurodegenerative disorder worldwide, frequently presents with early-stage speech impairments. Recent advancements in Artificial Intelligence (AI), particularly deep learning (DL), have significantly enhanced PD diagnosis through the analysis of speech data. Nevertheless, the progress of research...

Automatic reading diagnosis systems can benefit both teachers for more efficient scoring of reading exercises and students for accessing reading exercises with feedback more easily. However, there are limited studies on Automatic Speech Recognition (ASR) for child speech in languages other than English, and limited research on ASR-based reading dia...

This paper introduces an innovative methodology developed within the Homo Medicinalis (HoMed) project for adapting automatic speech recognition (ASR) models to handle sensitive audio data domains, specifically focusing on privacy-sensitive patient-provider medical consultations. By utilizing AI and deep learning algorithms, the project successfully...

This study addresses the need for accurate transcriptions of medical consultations using state-of-the-art (SOTA) open-source automatic speech recognition (ASR) systems. Efficient and secure speech-to-text conversion is crucial in healthcare for improved medical documentation, research facilitation, and patient confidentiality. The research compares...

We present a comparative study of a state-of-the-art traditional modular Automatic Speech Recognition (Kaldi ASR) and an end-to-end ASR (wav2vec 2.0) for a well-resourced language (Spanish) and a low-resourced language (Irish). We created ASRs for both languages and evaluated their performance under different update regimes. Our results show that t...

The last few years have witnessed an increasing demand for Automatic Speech Recognition (ASR) technology that can be successfully implemented in educational applications supporting the development of language skills. The main reason for this is the need for digital applications that can support the development of speaking and reading skills in the...

Automatic assessment of reading fluency using automatic speech recognition (ASR) holds great potential for early detection of reading difficulties and subsequent timely intervention. Precise assessment tools are required, especially for languages other than English. In this study, we evaluate six state-of-the-art ASR-based systems for automatically...

With recent advancements in automatic speech recognition (ASR), ASR-based educational applications have become increasingly viable. This paper presents a preliminary investigation into whether peer evaluations of the speech produced during the use of these applications, by primary school-aged children, is reliable and valid. Twenty-one Dutch primar...

Voicebots have provided a new avenue for supporting the development of language skills, particularly within the context of second language learning. Voicebots, though, have largely been geared towards native adult speakers. We sought to assess the performance of two state-of-the-art ASR systems, Wav2Vec2.0 and Whisper AI, with a view to developing...

Voicebots have provided a new avenue for supporting the development of language skills, particularly within the context of second language learning. Voicebots, though, have largely been geared towards native adult speakers. We sought to assess the performance of two state-of-the-art ASR systems, Wav2Vec2.0 and Whisper AI, with a view to developing...

The interest in employing automatic speech recognition (ASR) in applications for reading practice has been growing in recent years. In a previous study, we presented an ASR-based Dutch reading tutor application that was developed to provide instantaneous feedback to first-graders learning to read. We saw that ASR has potential at this stage of the...

Automatic assessment of reading fluency using automatic speech recognition (ASR) holds great potential for early detection of reading difficulties and subsequent timely intervention. Precise assessment tools are required, especially for languages other than English. In this study, we evaluate six state-of-the-art ASR-based systems for automatically...

Alzheimer's Disease (AD) is the world's leading neurodegenerative disease, which often results in communication difficulties. Analysing speech can serve as a diagnostic tool for identifying the condition. The recent ADReSS challenge provided a dataset for AD classification and highlighted the utility of manual transcriptions. In this study, we used...

Many digital services nowadays employ virtual agents and voice bots that can engage in spoken interaction with their users. This makes the communication more accessible and low-threshold, in particular for elderly people, low-literate and low-educated users. Another advantage of such systems that rely on spoken dialogues is that, with the user's co...

Children who go to a new country and have to function in a new school environment experience difficulties in learning their new second language (L2), especially when it comes to acquiring speaking skills. In particular, they miss opportunities to practice speaking the language and receiving feedback from their interlocutors. For these reasons, rese...

The European project SignON aims at designing a user-oriented and community-driven platform for communication among deaf, hard of hearing, and hearing individuals in both sign language and spoken languages (i.e. English, Dutch, Spanish, and Irish). Inclusion, easy access to translation services and the use of state-of-the-art Artificial Intelligenc...

This study tests the effectiveness of a CAPT tool tailored for Spanish L1 learners of Estonian to practice the perception and production of Estonian vowels. The tool is designed to train seven vowel contrasts (/i-y/, /u-y/, /ɑ-o/, /ɑ-ae/, /e-ae/, /o-ø/, and /o-ɤ/) that have been shown to be difficult for Spanish L1 learners. When practicing with th...

Learning to read is a vital skill to function in society. Unfortunately, an increasing part of Dutch adolescents have such poor reading skills that they risk becoming functionally illiterate as adults (Gubbels et al., 2019). As such, the issue of improving reading education should be addressed as early in children’s lives as possible. Personalised...

The current largest open-source generic automatic speech recognition (ASR) system for Dutch, Kaldi_NL, does not include a domain-specific healthcare jargon in the lexicon. Commercial alternatives (e.g., Google ASR system) are also not suitable for this purpose, not only because of the lexicon issue, but they do not safeguard privacy of sensitive da...

In this paper we present the currently running PDI-SSH project Homo Medicinalis (HoMed), in which we use machine learning to build an Automatic Speech Recognition (ASR) infrastructure for disclosing privacy-sensitive doctor-patient consultation recordings.

Reading is a learned skill that children acquire through instruction and practice. A desirable feature of that practice is that children can read aloud under the guidance of a teacher. Unfortunately, this is not always possible to a sufficient extent because of general time-constraints in teacher-fronted education. For this reason, experts have bee...

The interest in employing automatic speech recognition (ASR) in applications for reading practice has been growing in recent years. In a previous study, we presented an ASR-based Dutch reading tutor application that was developed to provide instantaneous feedback to first-graders learning to read. We saw that ASR has potential at this stage of the...

General-purpose automatic speech recognition (ASR) systems have improved in quality and are being used for pronunciation assessment. However, the assessment of isolated short utterances, such as words in minimal pairs for segmental approaches, remains an important challenge, even more so for non-native speakers. In this work, we compare the perform...

General–purpose automatic speech recognition (ASR) systems have improved their quality and are being used for pronunciation assessment. However, the assessment of isolated short utterances, as words in minimal pairs for segmental approaches, remains an important challenge, even more for non-native speakers. In this work, we compare the performance...

Recent advances on speech technologies (automatic speech recognition, ASR, and text-to-speech, TTS, synthesis) have led to their integration in computer-assisted pronunciation training (CAPT) tools. However, pronunciation is an area of teaching that has not been developed enough since there is scarce empirical evidence assessing the effectiveness o...

General–purpose state-of-the-art automatic speech recognition (ASR) systems have notably improved their quality in the last decade opening the possibility to be used in different practical applications, such as pronunciation assessment. However, the assessment of short words as minimal pairs in segmental approaches remains an important challenge fo...

The quality of speech technology (automatic speech recognition, ASR, and text–to–speech, TTS) has considerably improved and, consequently, an increasing number of computer-assisted pronunciation (CAPT) tools has included it. However, pronunciation is one area of teaching that has not been developed enough since there is scarce empirical evidence as...

Over the past few years the number of online language teaching materials for non-native speakers of Estonian has increased. However, they focus mainly on vocabulary and pay little attention to pronunciation. In this study we introduce a computerassisted pronunciation training tool, Estoñol, developed to help native speakers of Spanish to train thei...

Un par mínimo es un conjunto de dos palabras que difieren en sólo uno de los fonemas que constituyen su producción oral, cambiando por completo su significado. Existen programas informáticos que emplean pares mínimos para el entrenamiento de la pronunciación de lengua extranjera, principalmente para el inglés. En este artículo se presenta una herra...

In this document, we describe the mobile application Japañol 1 , a learning tool which helps pronunciation training of Spanish as a foreign language (L2) at a segmental level. The tool has been specifically designed to be used by native Japanese people , and implies a branch of a previous CAPT gamified tool TipTopTalk!. In this case, a predefined c...

A correct pronunciation is crucial to grasp an adequate communication ability in a foreign language. Nevertheless, traditional foreign language learning systems usually focus on the development of linguistic competencies related to grammar or lexicon. The quality of spoken language technologies (speech synthesis and recognition) has noticeably impr...

Availability and usability of mobile smart devices and speech technologies ease the development of language learning applications, although many of them do not include pronunciation practice and improvement. A key to success is to choose the correct methodology and provide a sound experimental validation assessment of their pedagogical effectivenes...

There are many software tools that rely on speech technologies for providing to users L2 pronunciation training in the field of Computer Assisted Pronunciation Training (CAPT) [1]. Currently the most popular mobile and desktop operating systems grant users a free access to several Text-To-Speech (TTS) and Automatic Speech Recognition (ASR) systems....

Feedback is an important concern in Computer-Assisted Pronunciation Training (CAPT), inasmuch as it bears on a sys-tem's capability to correct users' input and promote improved L2 pronunciation performance in the target language. In this paper, we test the use of synthetic voice as a corrective feedback resource. A group of students used a CAPT too...

This demonstration describes the TipTopTalk! mobile application , a serious game for foreign language (L2) pronunciation training, based on the minimal-pairs technique. Multiple Spoken Language Technologies (SLT) such as speech recognition and text-to-speech conversion are integrated in our system. User's interaction consists in a sequence of chall...

We present a foreign language (L2) pronunciation training serious game, TipTopTalk!, based on the minimal-pairs technique. We carried out a three-week test experiment where participants had to overcome several challenges including exposure, discrimination and production , while using Text-To-Speech (TTS) and Automatic Speech Recognition (ASR) syste...

We present a L2 pronunciation training serious game based on the minimal-pairs technique, incorporating sequences of exposure, discrimination and production, and using text-to-speech and speech recognition systems. We have measured the quality of users' production during a period of time in order to assess improvement after using the application. S...

Swain's (1985) Comprehensible Output Hypothesis considers that input alone may not be enough for second/foreign language (L2) learners to acquire new language forms. The Hypothesis claims that producing an L2 will facilitate L2 learning due to the mental processes related with language production. Thus, learners will more likely notice discrepancie...

Computer Assisted Pronunciation Training (CAPT) apps are becoming widespread to aid learning new languages. However, they are still highly criticized for the lack of the unreplaceable need of direct feedback from a human expert. The combination of the right learning methodology with a gamification design strategy can, nevertheless, increase engagem...

This paper introduces the architecture and interface of a serious game intended for pronunciation training and assessment for Spanish students of English as second language. Users will confront a challenge consisting in the pronunciation of a minimal-pair word battery. Android ASR and TTS tools will prove useful in discerning three different pronun...