そうそう

そうそう
interjection
yeah yeah, that's right
1. yeah yeah, that's right, exactly
Used in conversation to express strong agreement or to confirm what someone has said. Often signals that the speaker has just remembered or recognized something.
そうそう、それだよ。
Yeah yeah, that's it.
昨日(きのう)のニュース()た?」「そうそう、(おどろ)いたよね。」
"Did you see yesterday's news?" "Yeah, I was surprised."
そうそう、()(わす)れてたけど、来週(らいしゅう)予定(よてい)()わったよ。
Oh right, I forgot to mention — next week's plans have changed.

USAGE:
そうそう serves two main conversational functions:
1. Enthusiastic agreement — confirming what someone just said, stronger than a single そう
2. Recollection — introducing something the speaker just remembered, similar to "oh right" or "speaking of which"

The repetition of そう adds emphasis and casualness. In polite conversation, a single そうですね would be preferred.