It is estimated that there are 27,000 people with an Intellectual Disability (ID) in Ireland alone with a further 45,000 having a diagnosis of Autism. Almost all of these individuals experience difficulty in the development of their language. It is essential to have accurate assessments to diagnose their language difficulties. This project proposal aims to develop a computerized assessment of complex syntax. Despite the fact that proficiency in complex syntax is considered to have a large impact on educational success, we currently have very little information regarding typically developing children’s receptive knowledge of complex sentences. No detailed assessment of complex syntax exists anywhere in the English-speaking world. This project proposal aims to address this need. This proposal will also categorize error patterns which will in turn indicate appropriate points of entry for speech and language intervention in relation to these structures.