This article focuses on the use of natural language processing (NLP) to facilitate second language learning within the context of academic English. It describes a full cycle of educational software development, from needs analysis to software testing. Two studies are included: 1) the needs analysis conducted to develop the Intelligent Sentence Writing Tutor (ISWT) which diagnoses and at request corrects second language errors in writing, and 2) the summative evaluation of ISWT. The former comprises a survey of learning styles and learner corpus analysis which have both fed into the development of ISWT. The latter is addressed in a quantitative study with elements of both within-sample and comparison design. Due to the interdisciplinary nature of the examined phenomenon, the paper establishes links to previous and concurrent research in the fields of second language acquisition and ICALL (intelligent computer assisted language learning), while relying on a variety of theories and approaches to address a specific educational problem. The comprehensive coverage of the development process takes precedence over the fine detail of individual development stages.