Skyrim IV: Oblivion

[AsteriskAmp]

So, hey! Ijust found a black soul gem. How rare are these?

Also, I now know a bunch of words, but only 1 for each except for Fus Ro Dah. How do I increase my phrases?

They are a common item, in the sense that there are infinite of them but they are rather rare to find naturally (instead of bought).

Ask the Greybeards or shout in public places. That way you get sent to word walls.