Hard reset in Intl unlocked Dell venue Pro

Hi Everybody!. I bought an unlocked Dell venue pro device from ebay, so far it has been a great phone, but it came in english and i speak spanish mostly. I read somewhere that all wp7 devices come with some factory default languages, including spanish, but some carriers restrict the languages to english and that if a hard reset is performed, the languages become selectable. so, here is my question:

If I perform a hard reset in my unlocked dell venue pro, will it lock again? and I will become unable to use a foreign sim card as i am using right now?

Please, if you can help me, I'll greatly appreciate it, i'm terrified to do it and reset my phone into a brick state. getting another unlock code is near impossible according to other post i read here.

Carlos.