This work is based on a contrastive analysis of the linguistic changes patients suffering from Alzheimer's disease go thorough versus the linguistic capacities of normal subjects. This contrast is based on an extensive analysis of material of linguistic, psychological and medical nature in addition to my own experience working with Alzheimer's disease patients. As a basic theoretical component an extensive revision of concepts related to memory, specifically the semantic memory, and the development of the Alzheimer's disease and a discussion based on the particular development of the "living" category as an indicator of the semantic damage caused by the Alzheimer's disease is detailed.