The universalist view that acquisition of phonology is guided by universal principles has been the dominant position for decades. More recently, an alternative view has brought into focus the relationship between developmental markedness and language-specific input frequencies. With entirely original chapters on non-ambient-like productions by typically and atypically developing children, and second language learners, Unusual Productions in Phonology delves deeply into these competing explanations to show that patterns observed do not uniquely lend themselves to one or the other explanations. Rather, they point towards the need for both universal markedness and statistical input considerations in any attempted explanation. Containing contributions from leading researchers from around the world, this impressive collection is a must-have resource for any researcher, practitioner, or advanced student specializing in phonology, cognitive psychology, applied linguistics, and communication disorders.