This thesis investigates whether bilingualism affects children’s perceptual
acquisition of the speech sounds of their native languages. The term
bilingual is used here as synonymous with simultaneously bilingual, i.e.
those speakers of (typically) two languages who have been exposed to both
languages from birth.
This study takes an experimental approach. Bilingual and monolingual
children and adults participated on a longitudinal study in which their
perception of a Dutch vowel contrast was tested. Participants’ responses
were analysed in terms of cue reliance, i.e. how much they rely on
different acoustic cues in their perception of a speech contrast. The
results discussed here suggest that, although at a certain point in their
development bilingual and monolingual children have identical perceptual
behaviour, they differ in their developmental paths. This finding is in
line with the main literature on bilingual perceptual development. However,
the findings in this study are unusual in how this difference takes places.
Although patterns of bilingual delay and acceleration have both been
previously attested, the bilingual learners in the current study show both
patterns simultaneously, regarding different acoustic properties on the
perception of the same contrast. This thesis claims that the difference
found between bilingual and monolingual children is the consequence of two
factors: (i) the nature of the language input to the learner, and (ii) the
interaction between the bilinguals’ linguistic systems. The study presented
in this dissertation is of interest to researchers working on bilingualism,
language development and speech perception in general.