Developing English Vowel Contrasts: An Analysis of Spanish L1 Learners' Speech Production over Time in the UK

Languages vary in the complexity of their phonemic inventories. Potentially, vowels can possess contrastive features in respect of relative duration, quality, tone and nasality. However, not all languages use all of these features in the production or perception of sounds (Martínez-Celdrán & García, 2019; Ronquest, 2018). For example, Spanish has a simple vowel system in contrast to English which has a more complex vowel system with temporal and spectral differences only. Previous studies have observed that adult Spanish learners struggle to meet the complex target that English presents (Rato & Carlet, 2020). The present research involves the testing of a group of 40 native Spanish-speaking postgraduate students from their arrival at a UK university to the end of their first year of study. In particular, this study examines how the progress in developing the contrasts of English vowel pairs /iː/- /ɪ/; /ɪ/ - /e/ and /uː/ - /ʊ/, is reflected and managed by adaptations towards native-like English vowel pronunciation with respect to vowel quality and temporal features. To this end, Spanish speaking participants were recorded reading a list of words and reading passages at three time points over a year. The analysis was based on formant frequencies and phone duration. The formant values were obtained using Praat software and the degree of separation between the pair of tokens was determined by calculating Euclidean distances. In addition, vocalic changes were judged perceptually by native English lay listeners.
Results showed differential rates of progress across members of the group. The differences may be explained by the students' varying exposure to, and engagement with, native English speakers during their year of study in the UK. The results shed light on adult L2 production learning processes and the quantity and quality of time needed for adapting to the new L2 segments.