Processability Theory

Processability theory is a theory of second language acquisition developed by Manfred Pienemann and used as a framework by researchers across Europe, North America, Asia and Australia. It is a cognitive approach to second language acquisition that seeks to explain both developmental schedules and variation among learners, built on Willem Levelt's approach to language generation and formally operationalized using Lexical-Functional Grammar. Its core assumption is that learners can produce only what they are able to process, so learners are constrained to follow a hierarchical order of processability in acquiring any target language; applied to English as a second language, this predicts that word order stays initially limited to canonical word order even in questions, since operations such as do-support and auxiliary inversion require processing resources not yet available. The theory also includes modules addressing first-language transfer, variation among learners and the role of linguistic typology, and has been applied both to second-language classrooms and to linguistic profiling.