The acoustic properties of foreigner-directed speech are surprisingly understudied, and many existing studies evoke imagined interlocutors to elicit foreigner-directed speech. In this study ten native English speakers described the path between landmarks on a map to two confederate listeners (one native English speaker and one native Mandarin speaker) and to two imagined listeners (described as a native English speaker and a non-native speaker). Vowel duration, rate of speech, and vowel space size were examined across native-foreigner and real-imagined conditions. Stressed vowels were longer and rate of speech was slower in the foreigner-directed and imaginary conditions than in the native-directed and real ones. Vowel space differences were not significant. So, speakers made acoustic-phonetic adjustments in foreigner-directed speech that are consistent with those seen in listener-directed clear speech, and these accommodations were greater when the listener was imagined rather than real.