The role of input variability and learner age in second language vocabulary learning

Input variability is key in many aspects of linguistic learning, yet variability increases input complexity, which may cause difficulty in some learning contexts. The current work investigates this trade-off by comparing speaker variability effects on L2 vocabulary learning in different age-groups. Existing literature suggests that speaker variability benefits L2 vocabulary learning in adults, but this may not be the case for younger learners. In this study, native English-speaking adults, 7-8 year-olds, and 10-11 year-olds learned six novel Lithuanian words from a single speaker, and six from eight speakers. In line with previous research, adults showed better production of the multi-speaker items at test. No such benefit was found for either group of children either in production or comprehension. Children also had greater difficulties in processing multiple-speaker cues during training. We conclude that age-related capacity limitations may constrain the ability to utilise speaker variability when learning words in a new language