The overarching aim of this PhD dissertation is to examine how phonetic variation in spoken English affects speech perception and word recognition for late second language (L2) listeners. Through a series of experimental studies, targeting both offline perception and online processing, the project investigates (i) how comprehensibility, accentedness, and intelligibility vary across native and non-native English accents, (ii) how cross-language vowel perception shapes L2 listeners’ ability to identify English vowel categories, and (iii) how phonetic variation across various English accents impacts spoken word recognition. Together, the findings of these studies will provide a comprehensive understanding of how L2 listeners navigate phonetic variability in the speech of L1 and L2 speakers of English.