Going beyond mere grammaticality, the author examines the basic writing skills of a group of community college students in Hawaii for errors in idiomaticity, or native-like appropriateness of expression. («The Way of My Life», for example, though grammatical, is unidiomatic compared to «My Way of Life»). Criteria are suggested for the classification of
phrasematic expressions, and a convenient terminology comprising idioms, collocations, and formulas is developed. Increased attention to idiomaticity is required, not only in language description, but also in the academic writing of second language and creole speakers.