As the title of the thesis indicates, this study intends to investigate language performance and impairment elicited in the speech sample of some Iraqi patients diagnosed with Alzheimer's. The problem of this study is to see whether Alzheimer's disease affects its patients' language, and if so, what areas of language it affects. The aim of this study is to inspect and to explain both language performance and impairment of Alzheimer's patients during the disease. It hypothesizes that Alzheimer's patients suffer from sound substitution and omission on the phonological level. On the semantic...