Topic-174: The Balance Between Phonetic Forces In order to explain the sound patterns of a language, the views of both speaker and listener are considered. Both of them like to use the least possible articulatory effort (except when they are trying to produce very clear speech, and there area large number of assimilations, with some segments left out, and other reduced to minimum. Thus a speaker uses language with an ease of articulation (e.g., co- articulation and secondary articulation. This tendency to use language sounds with maximum possible ease of articulation leads to change in the pronunciation of words. In co-articulations, for example, a change in the place of the nasal and the following stop occurred in words such as improper and impossible before these words came into English through Norman French. In words such as these, then that occurs in the prefix in- (as in intolerable and indecent) has changed tom. These changes are even reflected in the spelling. In all this and in many similar historical changes, one or more segments are affected by adjacent segments so that there is an economy of articulation. These are historical cases of the phenomenon of assimilation. Similarly, articulation with the least possible effort enables us to speak by keeping the balance between phonetic forces ultimately leading to changes in the pronunciation of sounds. This idea is explained in the next topic.