Risa

it’s possible that they only use that weird allegory reference pattern when speaking formally to strangers or whatever

It seems like an awfully bad idea to use a communication method that doesn't transfer what you mean if you have a better option available.

It’s also possible that their language in the original version makes more sense and is more practical and it just gets mangled by the universal translator.

I doubt that's the case. I don't see how a non-metaphor based language would get turned into a metaphor based one through a software bug. Some big hand waving would need to happen for that.

IMO the Tamarians probably have brains that are structurally different such that their metaphors come far more naturally.