This study tested the hypothesis that factors that shape children's production of their native language (L1) will also influence adults’ pronunciation of sounds in a foreign language (L2). The final stops in CVC English words produced by 12 adult native speakers each of English, Polish, Spanish, and Chinese were phonetically transcribed. The frequency with which these stops were devoiced, deleted, or fricativized was tabulated. The Spanish subjects (unlike the Chinese or Poles) showed the effect of a transfer process, producing word-final /b, d, g/as fricatives. Subjects in all three non-native groups (but not the native English subjects) resembled English-learning children in devoicing word-final /b, d, g/. Subjects whose L1 does not have word-final stops (i.e., the native speakers of Chinese and Spanish) showed another process commonly observed in English L1 acquisition: final stop deletion. A number of language background variables (e.g., age of arrival in the United States) were found not to be significantly correlated with the accuracy of final stop production. These findings suggest that, in addition to transfer processes arising from L1/L2 phonetic and phonological differences, developmental processes similar to those affecting child L1 speech production also influence adult L2 speech production. © 1984, Cambridge University Press. All rights reserved.