Anecdotal evidence suggests that unfamiliar languages sound faster than one’s native language. Empirical evidence for this impression has come from explicit tempo judgments. However, it is unknown whether such perceived rate differences between native and foreign languages (FLs) have effects on implicit speech processing.

Our measure of implicit perception was ‘rate normalization’: Dutch and German listeners interpret vowels midway between /ɑ/ and /a:/ more often as /a:/ if the target vowel follows a fast (vs. slow) sentence. We asked whether such a ‘rate normalization’ effect may be observed when the context is not actually faster but simply spoken in a foreign language.

Dutch and German participants listened to Dutch and German (rate-matched) fast and slow sentences, followed by non-words that contained vowels from an /a-a:/ duration continuum. Participants indicated which vowel they heard (fap vs. faap). Across three experiments, we consistently found that German listeners reported more /a:/ responses after foreign sentences (vs. native), suggesting that foreign sentences were indeed perceived as faster. However, mixed results were found for the Dutch groups. We conclude that the subjective impression that FLs sound fast may have an effect on implicit speech processing, influencing how language learners perceive spoken segments in a FL.