"speaking much, very talkative," 1650s; from Latin multi- "much" (see multi-) + loqui "to speak" (from PIE root *tolkw- "to speak").
Entries linking to multiloquent
multi-
before vowels mult-, word-forming element meaning "many, many times, much," from combining form of Latin multus "much, many," from PIE *ml-to-, from root *mel- (2) "strong, great, numerous." It was much-used in forming Latin compounds in classical times and after (such as multianimis "having much courage," multibibus "much-drinking," multicomus "having much hair," multiloquus "talkative"). Many English words that use it (multinational, etc.) are 20c. coinages.
*tolkw-
Proto-Indo-European root meaning "to speak."
It forms all or part of: circumlocution; colloquium; colloquy; elocution; eloquence; grandiloquence; interlocution; interlocutor; locution; locutory; loquacious; loquacity; loquitur; magniloquence; magniloquent; obloquy; soliloquy; somniloquy; vaniloquence; ventriloquism; ventriloquy.
It is the hypothetical source of/evidence for its existence is provided by: Latin loqui "to speak;" Old Irish ad-tluch- "to thank," to-tluch- "to ask;" Old Church Slavonic tloko "interpretation, explanation."