This study compares phonetic implementation of the stop voicing contrast produced in Arabic by Saudi Arabians and by both Americans and Saudis in English. The English stops produced by Saudis manifested temporal acoustic correlates of stop voicing (VOT, stop closure duration, and vowel duration) similar to those found in Arabic stops. Despite such phonetic interference from Arabic to English, however, American listeners generally had little difficulty identifying the English stops produced by the Saudis, with the exception of /p/. This phoneme, which is absent in Arabic, was frequently produced with glottal pulsing during the stop closure interval. The timing of /p/, however, suggests that the Saudis did grasp the phonological nature of /p/ (i.e., that the contrast between /p—b/ is analogous to that between /t—d/ and /k—g/) but were unable to control all the articulatory dimensions by which this sound is produced. © 1981, Sage Publications. All rights reserved.