Does timing matter?: Exploring different windows of maximal opportunity to enhance the effectiveness of high variability phonetic training

A large body of literature has examined perceptual training, especially using the high variability phonetic training (HVPT) technique, where multiple talkers are included in the training set to help learners develop more accurate additional (second) language (L2) speech sound categories. Yet, most experimental studies focus on relatively short-term gains using a pre-post–delayed design, providing limited insight into longer-term training effects and how the timing of training might regulate its effectiveness. To begin addressing this gap, we implemented HVPT at two contextually relevant windows of opportunity during a university study program. Thirty-six first (native) language Spanish students participated in this study. Students were randomly assigned to two groups. One group (G1) received training at the beginning of their study program, which coincided with the onset of intensive L2 exposure; the second group (G2) received training in the second year, while enrolled in an English phonetics and phonology course. Both groups completed four HVPT sessions (identification tasks) focusing on a set of challenging L2 English vowels (/iː ɪ æ ʌ ɜː e ɒ ɔː/). Perception was measured at four testing times (in years 1 and 2, before and after HVPT) with identification tasks. The results showed that HVPT had a positive impact regardless of the timing of its implementation. However, students also improved outside of training, which suggests that intensive language study can facilitate some perceptual learning.