loquacious (adj.) Look up loquacious at Dictionary.com
1660s, a back-formation from loquacity, or else formed from stem of Latin loquax (genitive loquacis) "talkative," from loqui "to speak" (from PIE root *tolkw- "to speak") + -ous. Compare French loquace, Spanish locuaz. Related: Loquaciously; loquaciousness.