Marilyn Vihman

Experimental studies have shown that, from the first months of life, advancing neuromotor control affects perceptual processing, influencing the discrimination and categorization of consonants, for example. The key production milestone is the emergence of canonical babbling (i.e., babble involving CV syllables, at 6-8 months, typically). Adult-like babble gradually increases in frequency over the next few months, leading to the stabilization of at least one or two consonants. There is growing evidence that as stable consonant production emerges, it has the effect of orienting or focusing infant attention on ‘good enough’ matches in input speech. Listening through the filter of one’s own production routines results in the child retaining often- heard whole-word forms, such as baby, daddy, no; these are the forms that turn up again and again as the child’s first identifiable words.

This is the articulatory filter effect: The child’s own frequently produced consonants (or syllables) find echoes in input speech. Syllables and longer sequences repeatedly heard begin to be retained as wholes, becoming linked to their episodic or situational context. This in turn can lead to priming from routine situations, such that experience of a ‘bye-bye’ situation, for example, may elicit a [baba]-vocalization from the child. The ‘selectivity’ of the first words, which (i) target simple word forms that are also (ii) similar to the individual child’s babble patterns and (iii) quite accurately produced, can be explained in terms of this implicit ‘filtering’ of the input by the child. In short, vocal practice, especially after the emergence of adult-like syllable production, affects the way infants process speech, leading them to attend more to – and by implication better retain and represent – those patterns that roughly match their own vocal output, with which they have both proprioceptive and auditory experience.