Is text-to-speech synthesis ready for use in computer-assisted language learning?

Abstract

Text-to-Speech (TTS) synthesis, the generation of speech from text input, offers another means of providing spoken language input to learners in Computer-Assisted Language Learning (CALL) environments. Indeed, many potential benefits (ease of creation and editing of speech models, generation of speech models and feedback on demand, etc.) and uses (talking dictionaries, talking texts, dictation, pronunciation training, dialogue partner, etc.) of TTS synthesis in CALL have been put forward.Yet, the use of TTS synthesis in CALL is not widely accepted and only a few applications have found their way onto the market. One potential reason for this is that TTS synthesis has not been adequately evaluated for this purpose. Previous evaluations of TTS synthesis for use in CALL, have only addressed the comprehensibility of TTS synthesis. Yet, CALL places demands on the comprehensibility, naturalness, accuracy, register and expressiveness of the output of TTS synthesis. In this paper, the aforementioned aspects of the quality of the output of four state-of-the-art French TTS synthesis systems are evaluated with respect to their use in the three different roles that TTS synthesis systems may assume within CALL applications, namely: 1) reading machine, 2) pronunciation model and 3) conversational partner (Handley and Hamel, 2005). The results of this evaluation suggest that the best TTS synthesis systems are ready for use in applications in which they 'add value' to CALL, i.e. exploit the unique capacity of TTS synthesis to generate speech models on demand. An example of such an application is a dialogue 1

Usability assessment of text-to-speech synthesis for additional detail in an automated telephone banking system

“…The results are in agreement with previous research in a computer aided language learning (CALL) application (Handley, 2009), in which a sample of seventeen language professionals (teachers and researchers) rated the adequacy and acceptability of various TTS systems for use in a variety of teaching roles (e.g. as pronunciation model, conversational partner etc).…”

Accesibilidad de los contenidos en un repositorio institucional: análisis, herramientas y usos del formato EPUB

“…Además de la funcionalidad y la aceptación de los estándares mencionados, EPUB3 incorpora muchas facilidades para el soporte de accesibilidad (Handley, 2009). Una de ellas es el añadido de tres nuevas tecnologías complementarias que permiten a las autoras y los autores de 2.3 Extensiones de EPUB para TTS 5 Esta funcionalidad permite agrupar un conjunto de imágenes en un solo elemento de modo que solo se ve una de las imágenes y se puede cambiar de una imagen a otra usando botones.…”

Language and Text-to-Speech Technologies for Highly Accessible Language & Culture Learning

“…TTS is an interesting tool for users with reduced sight or with auditory learning preferences, who can use the TTS as reading machine (Handley 2009) (listen to instructions, theory, answer possibilities), and the technology also offers many didactical benefits for foreign language learning. However, these have been not much exploited so far.…”

“…It is clear that although over the years TTS technology has faced a lot of difficulties acquiring the complexity of naturally sounding speech, it has now reached a level of readiness for CALL applications despite imperfections remaining at the level of accuracy, naturalness and expressivity (Handley 2009). Research exploring further potential didactic uses of the technology and the evaluation of their specific plus-value is needed.…”