Learning English vowels with different first-language vowel systems II: Auditory training for native Spanish and German speakers

TLDR

The study examined whether speakers with small versus large native vowel inventories learn English vowels differently, aiming to clarify how L1 categories interfere with L2 vowel acquisition. Spanish (5 vowels) and German (18 vowels) listeners underwent five high‑variability auditory training sessions, with pre‑ and post‑tests measuring English vowel identification, assimilation into L1 categories, and perceptual vowel space maps. German participants improved more than Spanish after training, but Spanish listeners caught up after ten additional sessions, and both groups retained gains, indicating that larger vowel inventories and auditory training enhance automatic, efficient L2 vowel categorization.

Abstract

This study investigated whether individuals with small and large native-language (L1) vowel inventories learn second-language (L2) vowel systems differently, in order to better understand how L1 categories interfere with new vowel learning. Listener groups whose L1 was Spanish (5 vowels) or German (18 vowels) were given five sessions of high-variability auditory training for English vowels, after having been matched to assess their pre-test English vowel identification accuracy. Listeners were tested before and after training in terms of their identification accuracy for English vowels, the assimilation of these vowels into their L1 vowel categories, and their best exemplars for English (i.e., perceptual vowel space map). The results demonstrated that Germans improved more than Spanish speakers, despite the Germans' more crowded L1 vowel space. A subsequent experiment demonstrated that Spanish listeners were able to improve as much as the German group after an additional ten sessions of training, and that both groups were able to retain this learning. The findings suggest that a larger vowel category inventory may facilitate new learning, and support a hypothesis that auditory training improves identification by making the application of existing categories to L2 phonemes more automatic and efficient.