vocal (adj.)

late 14c., "spoken, oral," from Old French vocal (13c.), from Latin vocalis "sounding, sonorous, speaking," as a noun, "a vowel," from vox (genitive vocis) "voice" (from PIE root *wekw- "to speak"). In reference to music (as opposed to instrumental), first recorded 1580s; meaning "outspoken" first attested 1871. Vocal cords is from 1872; see cord.