The definition for "countervail" included this:
"Ultimately, from the Indo-European root wal- (to be strong) that is also the source of valiant, avail, valor, and value."
I wonder if wali (Encarta Encycl. "Wali, honorific title in Islam, given to a saint or wise and holy person, especially to the Sufi masters. In Arabic it means “defender, companion,...") is related?

In Arabic it means “defender, companion,...") is related?

I doubt it. Arabic descends from a (reconstructed) Proto-Semitic (as do Hebrew, Aramaic, and Amharic). Proto-Indo-Eruopean is reconstructed from the various Indo-European languages. To go back farther is probably not possible. (Although some have tried. You might look for a Nostratic forum to ask.) It's probably just a chance similarity.

Isn't it interesting how different languages developed? Some more vowelized, some more consonantized, some melodic, some harsh-sounding; then there are languages such as Chinese: does that even have vowels and consonants? Lots of dependence on intonation, I understand. And, I was just thinking yesterday about the African languages that include clicking (can't think of what that's called), and how that might have developed, as in: perhaps people started using a particular group of clicks to mean, say, run; then added...uh, what to call it?--sounds that could be spelled, perhaps--for different pre-/suffixes, tenses, or something. Click-oo would mean running, click-ah would mean ran. [shrug]