Establishing New Mappings between Familiar Phones: Neural and Behavioral Evidence for Early Automatic Processing of Nonnative Contrasts

Abstract

To attain native-like competence, second language (L2) learners must establish mappings between familiar speech sounds and new phoneme categories. For example, Spanish learners of English must learn that [d] and [ð], which are allophones of the same phoneme in Spanish, can distinguish meaning in English (i.e., /deɪ/ "day" and /ðeɪ/ "they"). Because adult listeners are less sensitive to allophonic than phonemic contrasts in their native language (L1), novel target language contrasts between L1 allophones may pose special difficulty for L2 learners. We investigate whether advanced Spanish late-learners of English overcome native language mappings to establish new phonological relations between familiar phones. We report behavioral and magnetoencepholographic (MEG) evidence from two experiments that measured the sensitivity and pre-attentive processing of three listener groups (L1 English, L1 Spanish, and advanced Spanish late-learners of English) to differences between three nonword stimulus pairs ([idi]-[iði], [idi]-[iɾi], and [iði]-[iɾi]) which differ in phones that play a different functional role in Spanish and English. Spanish and English listeners demonstrated greater sensitivity (larger d' scores) for nonword pairs distinguished by phonemic than by allophonic contrasts, mirroring previous findings. Spanish late-learners demonstrated sensitivity (large d' scores and MMN responses) to all three contrasts, suggesting that these L2 learners may have established a novel [d]-[ð] contrast despite the phonological relatedness of these sounds in the L1. Our results suggest that phonological relatedness influences perceived similarity, as evidenced by the results of the native speaker groups, but may not cause persistent difficulty for advanced L2 learners. Instead, L2 learners are able to use cues that are present in their input to establish new mappings between familiar phones.

Keywords: L1 Spanish; L1 allophones; L2 English; MMN; allophonic split; novel contrasts; perceptual categorization; phonological status.

Figure 1

Relation between allophones and phonemes in Spanish (left) and English (right).

Figure 2

Frequency of response label by stimulus type and listener group.

Figure 3

Illustration of the structure of each of the three experimental blocks in our modified passive oddball paradigm. Stimuli shown in black correspond to the stimulus type that served as the standard for that experimental block. The two types of deviants for a particular block are shown in red and blue.

Figure 4

Mean d' scores by language group and contrast. Error bars represent one standard error of the mean.

Figure 5

Grand average RMS amplitude of the response by listener group (English (A), Spanish (B), and Learner (C)) and contrast ([idi]-[iDi], [idi]-[iRi], and [iDi]-[iRi]). The response to each pair represents the summary deviant response for each of the three contrasts (A as standard with B as deviant and vice versa). The solid black line in each figure represents the mean RMS amplitude [fT] to pooled standards.

Figure 6

Mean RMS amplitude of the MMN [fT] by language group and contrast. Each bar represents the difference between the summary deviant response (A as standard with B as deviant and vice versa) and the response to the pooled standards. Error bars represent one standard error of the mean. Asterisks indicate significant MMN responses.