inflection

(noun) a change in the form of a word (usually by adding a suffix) to indicate a change in its grammatical function. Synonyms: inflexion.

(noun) the patterns of stress and intonation in a language. Synonyms: prosody.

(noun) deviation from a straight or normal course. Synonyms: flection, flexion.

(noun) a manner of speaking in which the loudness or pitch or tone of the voice is modified. Synonyms: modulation.