Abstract: A method of computerized language instruction for a student. Based on data regarding past performance of the student, an adjustable speech recognizer is adjusted. An utterance is received from the student, and the utterance is processed using the adjusted adjustable speech recognizer. The adjustable speech recognizer may comprise an Automatic Speech Recognition (ASR) engine. A set of contexts is created. Each context includes a set of words and utterances selected to allow recognition of the words and utterances by a speech recognizer. For each context, a set of subcontexts is created. Each subcontext includes the words and utterances of the context and selected mispronunciations or misarticulations of the words and utterances of the context. Recursively passing a portion of a received utterance to an ASR engine is described.