Bilingual language development might be characterized by transfer, deceleration,
and/or acceleration, the first two being relevant for the language impairment
diagnosis. Studies on bilingual children’s productive phonology show
evidence of transfer, but little is known about deceleration in this population.
Here, we focused on phonological transfer and deceleration in L1 speech of
typically developing Polish-English bilingual children of Polish migrants to the
United Kingdom (aged 4.7–7). We analyzed L1 speech samples of 30
bilinguals and 2 groups of Polish monolinguals, matched to the bilinguals on age
or vocabulary size. We found that bilingual children’ speech (both
simultaneous and early sequential) was characterized by transfer, but not by
deceleration, suggesting that while phonological deceleration phases out in
children above the age of 4.7, transfer does not. We discuss our findings within
the PRIMIR model of bilingual phonological acquisition (Curtin et al., 2011) and
show their implications for SLT practices.