modulation - noun

a musical passage moving from one key to another

(electronics) the transmission of a signal by using it to vary a carrier wave; changing the carrier's amplitude or frequency or phase

rise and fall of the voice pitch

a manner of speaking in which the loudness or pitch or tone of the voice is modified

the act of modifying or adjusting according to due measure and proportion (as with regard to artistic effect)

modulation - thesaurus

inflection   intonation   transition