I just started trying out patch 5 and have to stop. Tav does NOT SHUT UP. Please give us an option to turn off the annoying stream of consciousness speech. Also, I want Sebille, Lhose, Beast, and Fane back

just go the audio settings
there are three options:
Always-Occasional-Never

As stated above, there are options for this in the audio settings. But I have seen a few mentions that "occasional" is still to frequent for some and I'll forward this onto the team.

As i watched some streams ...
It seem to me, like it depend on how do you controll your character ...

If you tend to click seven times in a row, any new click just few millimeters away from previous (as Wolfheart do for example) they indeed talk too much.
If you tend to click somewhere far, and then let your grop to reach that point (as Moonlight do for example) they are talking significantly less.

Personally I'm digging it. It actually makes the game feel exactly like good ol' Baldur's Gate 1&2. In classic BG, every click brought an audible response from the character, while combats had everyone shouting their catchphrase over each other. Good times

For what it's worth, I suggest for general movement/interacting the characters say something once until reselected is an option. 'occasional' could be between every 15-30 seconds maybe?