Your research is on children's acquisition of phonology. Could you describe the various stages of language learning in early childhood?
This is a central issue in my current research at the Collegium. According to the latest developments in the field and, more hypothetically, in my work in progress, children must first decode the system of sounds of their own languages (for example, what are these sounds? In what contexts are they found with respect to other sounds?) before they begin to acquire words. Once an early vocabulary is learned, the child uses it to explore the more subtle aspects of the language, such as the syntactic relations that take place between words.

What observational and analytical methods do you use? In which thematic and conceptual lines do you place your work?
My empirical work is based on longitudinal studies of language production in young learners. These studies generally cover from one to four years of linguistic productions, often starting from the moment when children produce their first words.
Thematically, my approach is fairly general in that it is concerned with the factors that influence language acquisition (such as the perception of sounds and combinations of sounds, or word storage in the brain), as well as some physiological and motor aspects related to the production of these words.
Conceptually, one might say that my approach is generativist in the broad sense of the term: I am interested in the notion of language faculty. Several current debates — that I consider important — call this approach into question, but these debates are often biased by misconceptions of certain aspects of this theory. I take a pragmatic approach: nobody can deny that human beings have an extraordinary aptitude for learning and the use of language. But this leaves unanswered the very important question of how to characterise this aptitude and understand how it fits in with the rest of the human cognitive system. This is the question that interests me, and I approach it from the standpoint of language acquisition.

You have studied young children's acquisition of phonology in a number of languages. As a specialist in prosody, have you observed any differences in language acquisition from one language to another? Or do you find similarities in the learning mechanisms?
The mechanisms are basically the same. However, the target languages, which all have distinctive features, influence the way in which these mechanisms express themselves. A child learning English, for example, tends to associate the beginning of words with the accented syllable, whereas a child learning French – a language in which the accent is generally placed at the end of the word or phrase – perceives his or her first words from that point of view. This example shows that accent is a key factor for learners of both languages, but that the position of the accent in each language influences the way that language is acquired.

Can you draw any conclusions yet?
Yes, though always with the caution required for sound scientific progress. My current work suggests that children evolve from relatively concrete acquisition of the words of their language – in memorised form, one might say – towards a more abstract, grammatical understanding. At an advanced stage in this acquisition process, the child will know how to divide the word into smaller parts: morphemes (e.g. prefixes, roots and suffixes), syllables and phonemes.

What are the implications of your work for society?
Every child in the world needs to learn how to speak. In fact, there are very few aspects of the way our societies work, regardless of their geographical origins, that are not partly or wholly based on communication through language. Although most individuals succeed in learning one language easily, 10% to 15% of children manage to do so only with a certain degree of difficulty, or in extreme cases not at all. This is significant. The better we understand the cause or, often, the causes of their difficulties, the more quickly we can diagnose problems and the more appropriately we can treat them, at least when treatment is possible. Since my research focuses not on one language in particular, but rather on the general mechanisms governing languages and language acquisition, anything I discover now and in the future, as well as the advances that these discoveries will make possible, will have the potential to benefit any child, especially in countries where language development is monitored through educational or health-related services.

You have been in residence at the Collegium de Lyon since September 2008 and will remain there until July 2009, and you are currently writing a book on children's phonological development. How has this resident fellow's post helped you in terms of contributing to your research and enhancing your already close contacts with Lyon's centres for research on language dynamics?
A great deal. Not only in Lyon but in several French and European research centres. My own research has benefited from an exceptional work environment, as it has allowed me to immerse myself in the latest developments in several fields of research on language acquisition. These developments will be synthesised in the book I am writing. More generally, the Collegium's position in Lyon's scientific community has enabled me to form ties with leading scholars, some of which will eventually yield collaborations on both theoretical and practical fronts. Discussions with many colleagues have helped me to identify certain bases for reconciling theories that are often considered as conflicting, particularly as regards the cognitive conceptualisation of linguistic representations. The research methods I have developed for studying acquisition have also proven useful to, for example, scholars specialising in African languages. Such technology transfer is not surprising since languages and the mechanisms that govern them are basically the same, but my stay at the Collegium has contributed to sharing of this sort. It has provided the platform required to facilitate the discussions and exchanges of ideas that are essential to the emergence of these connections, which have many, and fascinating, potential implications.