Abstract
Anecdotal evidence suggests that unfamiliar languages sound faster than one’s native language. This impression has been termed the ‘Gabbling Foreigner Illusion’ (Cutler, 2012; p.338) and is supported by empirical study. For example, German and Japanese listeners consistently overestimate the other language’s speech rate by about 7-9% (Pfitzinger & Tamashima, 2006). Instead of using explicit rate judgments, the present study set out to test whether the reported illusory rate difference between native and foreign languages would have effects on implicit speech processing.
Specifically, we used the effect of normalization for speaking rate as a measure of implicit rate perception. To illustrate, Dutch listeners interpret a vowel midway between /ɑ/ (short duration) and /a:/ (long duration) more often as /a:/ if the target word follows a fast (rather than a slow) sentence (Reinisch & Sjerps, 2013). That is, vowel length is perceived contrastively with the rate of the context. The crucial question of our study is whether such an effect may be observed when the context is not actually faster but simply spoken in a foreign language.
Dutch and German versions of 30 sentence contexts were recorded by a Dutch-German bilingual. Sentence pairs were semantically similar across languages and matched in number of syllables. Each sentence was linearly compressed or expanded to a fast and slow version with sentence durations matched across languages. Target ‘words’ contained vowels from a duration continuum from /ɑ/ to /a:/ and were nonwords in both languages. Pretests ensured that the vowel continuum was perceived identically by speakers of Dutch and German.
In Experiment 1, Dutch and German listeners were presented with all (fast, slow, Dutch, German) sentences followed by the ambiguous targets. Listeners were asked to decide which nonword they heard (e.g., fap vs. faap). The compressed sentences (fast) were expected to trigger more long-vowel responses relative to the expanded (slow) sentences. Similarly, if the ‘Gabbling Foreigner Illusion’ affects speech processing, then listening to one’s foreign language (German for Dutch listeners, and Dutch for Germans) should induce a perceptually faster rate, also leading to more long-vowel responses.
Results showed a consistent effect of rate normalization with more ‘long’ responses following the compressed sentences. Moreover, for German listeners, a language effect was found. Foreign (Dutch) sentences triggered more ‘long’ responses than native (German) sentences, suggesting that foreign sentences were indeed perceived as faster than native sentences. However, the opposite was found for the Dutch listeners. For them, their native language (Dutch) sounded faster rather than their foreign language (German).
Experiment 2 controlled for additional acoustic properties of the context sentences across the two languages. Even though this manipulation did reduce the language effect in the Dutch group significantly, the overall results were similar: both groups perceived Dutch as faster.
Taken together, we conclude that the subjective perception of speaking rate, as suggested by the ‘Gabbling Foreigner Illusion’, may have an effect on speech processing, as shown by the German group. Potential explanations for variation between the two listener groups may be related to varying language proficiency.
