I have heard 'loquacious' a few times but I have never even heard 'garrulous'. There is a point at which a word is too rare and fanciful to be used, especially in speech. Either no one understands you, or they think you are trying too hard to seem smart, or both! It is best not to do it... and both of these words are good examples of this. But, to answer your question, it looks like they are more or less exact synonyms of 'talkative'. Just say talkative unless you are writing poetry or fancy prose.

Both mean "talkative". The difference is that "garrulous" is exceesive talk on trivial things; also can be long winded. These are two great words to describe chatterboxes. Knowing how to use big words properly is important. Let not those who are mediocre pull you down to their level. His garrulous reminiscences show how much he had missed his youth. It is not the loquaciousness of the talkshow host that generates the high ratings but its salacity!

Teachers often tell their students they are being "loquacious" as a fun synonym for "talks too much", while framing it as a positive character trait. "You're being loquacious, let's keep quieter! (Smile)" By often, I mean 15% of teachers may utilize this word in that context, and that's only in school. Loquacious is a word that isn't needed - it has replacements like "chatty", or "talkative", that a person would uses hundreds of times before dusting off the big word. Garrulous is a word that isn't even used, except on old SAT tests.

I don't think there's any difference. Both are rather "literary" words. The everyday word is "talkative." Understand "loquacious" and "garrulous" but just use "talkative" yourself.

They are both words that aren't used that much in everyday speech and I'm not sure I've ever really seen garrulous except in some books - I just had to look it up to remember the meaning. Loquacious is someone who talks a lot. It can be negative but can also describe someone who just likes to talk a lot in quite a social way. Usually it means they are very fluent with the language and may talk in quite a wordy way using more words than are really needed or uncommon words that aren't normally used in everyday speech. I'd associate it with someone like Boris Johnson in the UK where the person sometimes speaks in quite a rambling way but is very fluent with the language.. Garrulous has a more negative connotation. It usually means excessive talking about things of little importance. Someone that just never stays quiet even if they have nothing really to say and quickly gets annoying to many people.