(noun) The tendency of a sound to be replaced by another, and this especially occurs with the consonants , and , as in the name Annabel dissimilating to Amabel, from which comes the name Mabel.
In phonology, particularly in historical phonology, dissimilation is a phenomenon whereby similar consonant sounds in a word become less similar. It is sometimes claimed that dissimilation results in a form that is easier for the listener to perceive (whereas assimilation results in a form that is easier for the speaker to pronounce), with the implication that such results are in fact the cause of the change. But all such speculations are without objective support.