Defining everything in terms of a single language (English) also creates avoidable problems.
That's why the terms should be defined.
I don't think it's actually necessary to start off with a monolingual glossary
We have to start somewhere, and I'm afraid that unless we direct attention we never get anything into useful state.
I think this would be a good moment to mention OmegaWiki,
I know about OmegaWiki, I even wrote my candidate's thesis about OmegaWiki and translatewiki.net. The conclusion was that it is not suitable for us. Terminology is different from what OmegaWiki is doing. And we are building a terminology, not a (multilingual) glossary. There are some ideas we could borrow, I don't deny that. Currently I'm exploring if we can take advantage of Semantic MediaWiki.