When learning a language,listeners must also learn to group sounds they hear into the categories relevant in that language(see speech sound learning, Box 4). Given that speech sounds are multi-featured and variable, single acoustic features cannot be used to learn these distinctions. Learning occurs in a probabilistic fashion and theoretically should involve procedural learning systems. A few studies have explored the brain systems involved in speech category learning [60,61]. A recent study examining the dynamics of non-native speech category learning in adults [60] showed that this learning is initially associated with activation in both hippocampal and corticostriatal circuits. Across learning trials ,participants’ behavioural responses indicated a shift from a rule-based strategy to one that is more procedural. In line with the crossover to a procedural strategy, the corticostriatal system showed increased activation during learning and was associated with better categorisation performance.