Request for comments/Help for starting project terminologies
Sure. We could then see if there's some overlap and they can be combined in some way.
With regard to Terminology/mediawiki, it's really a shame that there's no MediaWiki glossary (apparently, only w:en:Wikipedia:Glossary and Wikibooks:Help:Glossary), and we should create one, but probably not here, rather on mw:, where it would be of general use; on the contrary, I don't think that creating a complete MediaWiki glossary in all languages is really feasible.
The glossaries we need here should include only those terms whose translation is not obvious: terms with a very technical meaning, or words without a true equivalent, which are hard to translate or end up being translated in a number of different ways; such terms are a subset of the complete glossary + the list of other used words (which may have a clear meaning in English but still be hard to translate).
We could pick up from the general English glossary and word list the words we think are hard to translate and start to make a huge table with a row per term and a column per language; perhaps not all languages will need to establish an "official translation" for all/the same terms, but if there's some overlap it will be useful (and should address Purodha's concern).