original words in PIE come from,

Char. Limit

Where do the original words
in PIE come from, and why do languages tend to diverge rather than converge?

CRGreathouse

To the first question, we don't know. There are prominent lingusits who have suggested onomatopoeia as the ultimate root for many/most protolanguage roots, but I don't know that that theory is widely accepted.

On the whole, languages converge by borrowing and diverge by the natural sound changes by language users in different areas. That they diverge more converge suggests that borrowing is less common than sound change. (Of course there are other drivers for both.)

Char. Limit

But... We know everything about ourselves... I wish at least.

Thanks for the info.+