Speech acquisition within a 3-generation Vietnamese-English family: the influence of maturation and ambient phonology.

The emergence approach to speech acquisition theorises the influence of intrinsic capabilities (e.g., maturation), interactional capabilities, and extrinsic contexts (e.g., ambient phonology). Intrinsic and extrinsic influences were examined via a case study of a 3-generation Vietnamese-English family with two brothers (C1 aged 5;6 and C2 aged 3;10), their mother (M), grandfather (GF) and grandmother (GM). Their speech was assessed using the Diagnostic Evaluation of Articulation and Phonology (DEAP) and the Vietnamese Speech Assessment (VSA). Standard Australian English/Standard Vietnamese productions were defined as 'correct', even though the adults spoke different Vietnamese dialects. Their percentage of standard consonants correct (PSCC) was: C1 (English:92.27%, Vietnamese:89.05%), C2 (E:86.47%, VN:86.13%), M (E:90.34%, VN:96.35%), GF (E:82.61%, VN:97.81%), GM (VN:99.27%). Percentages were higher when dialectal variants were included. C1 and C2 had more pronunciation matches with English (86.96%) than Vietnamese (79.56%). C1's pronunciation matched: M (E:85.02%, VN:83.94%), GF (E:79.23%, VN:77.37%), GM (VN:73.72%) and C2's pronunciation matched: M (E:79.23%, VN:73.72%), GF (E:73.91%, VN:75.18%), GM (VN:72.26%). There was evidence of ambient phonology influences and cross-linguistic transfer. For example, in Vietnamese 'r' is produced as /ʐ/ or /r/ , but was produced by C1 as [ɹ] (English approximant) and by C2 [w] (age-appropriate/ɹ/substitution). The children demonstrated maturation influences for late-occurring English consonants (e.g., English /θ/ →[f]). This study found evidence for the emergence approach and recommends knowledge of the ambient phonology augments traditional child-focused understandings of children's speech acquisition.