2018 Sun Session A 0900

Sunday, November 4, 2018 | Session A, East Balcony | 9am

Infants track the languages used by individual speakers
C. Potter, N. Marayati, C. Lew-Williams

A major hurdle in early language learning involves distinguishing between meaningful differences and irrelevant inconsistency, such as variability in tokens, speakers, or accents (1-2). Early in development, infants are highly attuned to acoustic differences and readily distinguish between different speakers, as well as different languages (3-4). In monolingual environments, where all speakers use the same language, infants pay less attention to these distinctions (5-7). However, in multilingual environments, where different people may systematically or probabilistically use different languages, speakers offer a potentially valuable cue that infants could exploit. Indeed, for over a century, it has been suggested that bilingual infants could benefit from hearing their two languages spoken by different people (8-9), but a critical and foundational investigation is currently missing in our field: it is not yet known whether infants are able to track the language(s) used by different speakers. In the current study, we ask whether infants can learn pairings between speakers and languages and test whether they detect a change in the language used by a given speaker.

Method and Results. Monolingual English-learning 9-10-month-old infants (n=20) were familiarized with two talkers (one male, one female), each using a different language. One speaker (e.g., the male) always used English, while the other (female) always used Arabic, an unfamiliar language for all participants. Stimuli were recorded by bilingual speakers, and speaker/language pairings were counterbalanced across infants. During habituation, each speaker used one language exclusively. Infants heard a series of trials, consisting of English and Arabic sentences, which continued until infants’ looking time (calculated over a sliding window of three trials) decreased to <65% of looking time on the first three trials. At test, infants heard two Familiar trials where the speaker-language pairings were maintained, and two Novel trials where pairings were switched (Figure 1). All test trials involved identical speakers and languages; only the pairings varied, which controlled for idiosyncratic properties of the speakers’ voices, as well as interest in the native vs. non-native language. A paired-samples t-test revealed that infants listened reliably longer on Novel trials than on Familiar trials [t(19)=2.49, p=.02, see Figure 2]. Fifteen of 20 infants demonstrated a novelty preference, suggesting that they attended to the language used by each speaker.

Discussion. This study provides the first evidence that infants are able to track associations between speakers and languages and that they may expect speakers to remain consistent in their language use. Interestingly, during the same months when infants are first able to ignore differences between speakers to recognize the same word (6), they are not ignoring the interaction between speakers and languages. That is, critically, infants are not simply disregarding ‘surface-level’ speaker information, highlighting their well-calibrated ability to shift attention toward and away from different acoustic dimensions of speech. In ongoing studies, we are testing whether bilingual infants, whose environments include more complex speaker/language interactions, are sensitive to gradients in speaker/language associations. This investigation provides a valuable framework for understanding how infants use experience to weight different perceptual cues in their input.

References

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