Batman in Finnish

I was reading Sterling's Lego Batman book to him tonight and noticed something interesting about the Finnish translations of certain Bat terms. Some of them keep the "Bat-" prefix, while others use the Finnish word for bat (lepakko) instead.

Here we have 'Batman,' left as it is in English. But Batcave is 'lepakkoluola'. Batboat (?) is 'lepakkovene'. So far, we could draw the conclusion that Batman is Batman, but everything else gets the Finnish 'lepakko-' prefix.

But the next page has:

Batmobiili (Batmobile)! So there is at least one exception to the possible "Bat- for Batman and lepakko- for everything else" rule.

I remember translators agonizing over stuff like this when I worked at a translation company in Provo years ago. You usually can't just make it up as you go - there has to be a rule or a system. It's fine to translate Batcave as lepakkoluola the first time, but then you have to be consistent every other time, too. I'm sure there is a reason (possibly lost to the sands of time) that Batmobile keeps the bat-, but someone, somewhere had to make that decision at some point.

We rarely got to make such exciting distinctions at the translation company I worked at. The most exotic translation job I remember us getting was a scented candle catalog. Try translating something like "Caribbean Dreams" scent into seven other languages while preserving all cultural, alliterative, and linguistic references. Yeah.