Foreigner talk is the register used by native speakers to make themselves understood by foreigners whose competence in the language is limited. Published studies on foreigner talk have dealt with phonetic variation sparingly and impressionistically. This may be due to the difficulty of imposing experimental constraints on natural linguistic events without introducing excessive artificiality. A method is described permitting systematic analysis of a selected phonetic variable (voice onset time in fortis English plosives) in the context of naturalistic conversations between native speakers and foreigners of varying levels of competence in the language of communication. This paper is intended to encourage greater interest in foreigner talk and to improve the quality of data in experimental phonetics by bringing it closer to the encounter between speaker and listener. (Author/NCR)