Interested in Language
Can I say "expand" or "enrich" one's knowledge/vocabulary base?
Some people say "widen the tax base", does "widen" collocate with knowledge base too?
I am not a teacher.
I think that you could use any verb that expresses the idea of enlargement of a physical base, since that is the metaphor. They won't all be equally common in use but probably perfectly understandable.
I would suggest "broaden".