Without data on speech accuracy of Vietnamese-English speakers, speech-language pathologists (SLPs) are unable to assess accurately this population for speech sound disorders. This study explored the heretofore uninvestigated speech accuracy and use of Vietnamese-English bilingual individuals residing in the USA. Participants included six individuals from a 3-generation household (two US-born children and four Vietnam-born adults). Each participant completed a language history questionnaire and single-word articulation tests in Vietnamese and English. Percentage Consonants Correct -- Revised and Percentage Consonant Clusters Correct were compared across participants and generations. Phoneme errors were analysed to identify adult influence on child productions. Heritage language use and speech accuracy generally showed an inverse relationship with length of stay, but the children's productions were nearly without error in both languages. Only the mother exerted apparent influence on the children's speech development, though only in Vietnamese. The children's English productions were unaffected by any adult's productions. Clinicians working with children from this background should consider not only familial influence on speech sound accuracy but should anticipate high levels of speech accuracy in both English and Vietnamese. When working with adults, SLPs should be aware that deviant speech productions might be due to typical Vietnamese-English speech development.