Code-Switching in Highly Proficient Spanish/English Bilingual Adults: Impact on Masked Word Recognition

Abstract

Purpose: The purpose of this study was to evaluate the impact of code-switching on Spanish/English bilingual listeners' speech recognition of English and Spanish words in the presence of competing speech-shaped noise.

Method: Participants were Spanish/English bilingual adults (N = 27) who were highly proficient in both languages. Target stimuli were English and Spanish words presented in speech-shaped noise at a -14-dB signal-to-noise ratio. There were 4 target conditions: (a) English only, (b) Spanish only, (c) mixed English, and (d) mixed Spanish. In the mixed-English condition, 75% of the words were in English, whereas 25% of the words were in Spanish. The percentages were reversed in the mixed-Spanish condition.

Results: Accuracy was poorer for the majority (75%) and minority (25%) languages in both mixed-language conditions compared with the corresponding single-language conditions. Results of a follow-up experiment suggest that this finding cannot be explained in terms of an increase in the number of possible response alternatives for each picture in the mixed-language condition relative to the single-language condition.

Conclusions: Results suggest a cost of language mixing on speech perception when bilingual listeners alternate between languages in noisy environments. In addition, the cost of code-switching on speech recognition in noise was similar for both languages in this group of highly proficient Spanish/English bilingual speakers. Differences in response-set size could not account for the poorer results in the mixed-language conditions.

Figure 1.

Distribution of English and Spanish word recognition scores in speech-shaped noise for each experimental condition. Open boxes represent the performance for English targets, and grey boxes represent the performance for Spanish targets. The boxes represent the interquartile range (25th–75th percentile); the median score is indicated by the horizontal line dividing the boxes. Whiskers represent the 10th and 90th percentiles, and asterisks represent the maximum and minimum scores. In the mixed-language conditions, wider boxes represent the majority language (75%), while the narrower boxes represent the minority language (25%).

Figure 2.

Differences between single-language and mixed-language scores are shown with values for individuals on top of the box plots. Open boxes represent the performance for English targets, and grey boxes represent the performance for Spanish targets. The boxes represent the interquartile range (25th–75th percentile), the median score is indicated by the horizontal line dividing the boxes, whiskers represent the 10th and 90th percentiles, and open circles represent individual scores. In the mixed-language conditions, wider boxes represent the language of the majority of the words (75%), whereas narrower boxes represent the language of the minority of words (25%).

Figure 3.

Psychometric function comparing 4AFC (left) and 7AFC (right) tasks. Percent correct word recognition was estimated at 51 dB SPL. 4AFC = four-alternative forced choice; 7AFC = seven-alternative forced choice.