Babble

Babble is defined by the OED as a verb meaning:

1. To make imperfect attempts at speech, like a child; to utter inarticulate or indistinct sounds

2. To talk childishly, to prattle; to talk incoherently or foolishly; to utter meaningless words.

3. To talk excessively or inopportunely; to chatter, prate.

4. transf. of streams, brooks, etc.; also of young birds, and spec. of hounds that give tongue too loudly or without reason.

5. ? To waver, oscillate, quiver. Obs. [Perhaps a distinct word.]

6. To repeat or utter with meaningless iteration; to speak foolishly or incoherently; to prate.

7. To reveal by talking or chattering. Cf. blab.

It comes from the Middle English word babalen, and can't be traced back very far no matter which similar word in other languages you look at. When I looked this word up, I expected to find some connection to the tower of Babel from the Bible, but I found that no direct connection could be traced to connect the two. Instead, the dictionary hypothesized about its origins being in the nonsensical sounds that a baby makes.