The phrase "talks a blue streak" means to speak rapidly and with great enthusiasm, often to the point of dominating a conversation. Antonyms for this phrase would be words or phrases that convey the opposite meaning, such as "silent," "reserved," "muted," "soft-spoken," or "reticent." These words describe individuals who do not speak very much or who are not very expressive in their speech. Other antonyms might include "calm," "gentle," "placid," "peaceful," or "tranquil," which describe someone who does not speak in an excessively animated or boisterous manner. Whatever the antonym, it's clear that sometimes less is more when it comes to talking a blue streak.