Webster’s Revised Unabridged Dictionary · 1913
Modulate
Mod′u·late (mŏd′ū·lāt), v. t. [imp. & p. p. Modulated; p. pr. & vb. n. Modulating.] [L. modulatus, p. p. of modulari to measure, to modulate, fr. modulus a small measure, meter, melody, dim. of modus. See Mode.] 1. To form, as sound, to a certain key, or to a certain portion.
2. To vary or inflect in a natural, customary, or musical manner; as, the organs of speech modulate the voice in reading or speaking.
Could any person so modulate her voice as to deceive so many? Broome.
Mod′u·late, v. i. (Mus.) To pass from one key into another.