During its development, a child has to learn to select the sound elements that are compatible with its linguistic environment, and at the same time ignore those elements that are absent from the phonetic structures that it perceives in its usual surroundings. The child will acquire a linguistic coding by adjusting to the sound structures of its own language.
But because this coding is specific to each language, it will rapidly become a brake on the learning of a foreign language, insofar as the sounds of the foreign language do not conform to the sound patterns of its native language, which have been interiorized during infancy. A language is therefore first of all a kind of music, that is, an ensemble of specific rhythms and sounds. These rhythms and sounds constitute the fundamental sound substrate on which all other acquisitions will be based (for example, lexical, syntactical, and semantic acquisitions).