Adding prefixes and suffixes:
* Flabbergasted: This word implies being shocked and speechless, but it can also be used humorously to describe someone who talks too much.
* Jabberwocky: This nonsensical word from Lewis Carroll's "Through the Looking-Glass" can be used to describe someone talking gibberish or nonsensically.
* Chatterbox: A common word for someone who talks excessively.
* Mouthy: This word describes someone who is loud and opinionated, often in a negative way.
Phrases and idioms:
* Blabbermouth: Someone who can't keep secrets and talks too much.
* Talking a mile a minute: This describes someone who speaks very quickly.
* Running off at the mouth: This describes someone who talks excessively and often without thinking.
* Spouting nonsense: This describes someone who talks foolishly or without any real meaning.
Using language creatively:
* You could use a silly voice or exaggerated pronunciation.
* You could add in unnecessary sounds or words. "Like, uh, yeah, so, you know, like..."
* You could intentionally mispronounce words. "I'm going to the shoop, I need to buy some, uh, groories."
Remember, the best way to make "talk" sound foolish will depend on the context and your desired effect.