I don't mean that. I always use english in every game. Maybe the issue occur bacause miss coding/miss typo. None of us is perfect . Anyway total all language in the world is about 100 right? I think it's possible but required a tons of works .
Actually there is around 7000 languages in the world, though most don't have their own OpenXCom version yet.
And if it's English you're talking about... Well, all modders I know include an English version, though it's usually US version only, and sometimes it's GB version only. This can be checked easily by looking at the ruleset, even for a layman; look for extraStrings section (usually at the end, though not always) and see its subsections.