Profiling bilingual and minority language acquisition is becoming increasingly important for the work of speech and language therapists in Ireland. The Official Language Act dictates that all government and public services must be provided in Irish as well as English. Therefore SLTs must now be prepared to assess and treat clients in the Irish language. This paper describes how an assessment of early expressive vocabulary and grammatical development for children aged between 16 and 40 months was adapted to Irish from the MacArthur-Bates Communicative Development Inventories (Fenson, Dale, Reznick , Bates , Thal, Pethnick, Tomasello, Mervis and Stiles, 1994). Ongoing work in piloting and measuring the validity and reliability of the parent-report instrument is also outlined. This study has implications for developing assessment tools for working with Irish-speaking and bilingual children.