dis·sim·i·la·tion 
(dĭ-sĭm′ə-lāshən)
(dĭ-sĭm′ə-lāshən)n.
1. The act or process of making or becoming dissimilar.
2. Linguistics The process by which one of two similar or identical sounds in a word becomes less like the other, such as the l in English marble (from French marbre).