Does the game has Spanish language? on steam it has it but here the web only says english, I want to know that before I buy it, thanks :)

THE game?

Yes the game of course. Elder Scrolls Oblivion.

From what I know the GOG version lacks the other languages because some of the addons in the deluxe edidion have not been translated. If you check on Steam you will notice the GOTY edition has more languages but the deluxe edition is only in english

You're probsbly aware that this is an "ElderScroll series" forum (see forum title above).

Well, Oblivion GoTY "should" be the same in Steam and in GOG. Steam says Oblivion GoTY works in Spanish (without voice), and if this works (I haven't tried), the same should be possible for the GOG version. Have you searched the internet for oblivion gog spanish or similar? When I did a quick search, I saw this link:
https://www.reddit.com/r/oblivion/comments/19552l1/change_the_language_ovlibion_goty_deluxe_from_gog/
May or may not help. But at any rate, don't expect voices to work.

Ohhh ok thanks, yes I don't mind the english voices, only want spanish subtitules and I'm set :), thanks for the reply.

Are you sure about that? I have seen in several times being mentioned here the GOG lacks the languages - they are not the same. GOG does not have the GOTY edition. GOG have only the Deluxe edition which lacks the language packs.

No. I was assuming that two games sold under the name "Oblivion GoTY" are the same, That GOG adds "De Luxe" to the title doesn't sound like less content, and the DLCs included are the same.
I saw that Steam mentions support for Spanish, but I didn't check GOG.
I just saw that GOG lists English support only - no Spanish mentioned - no cheating involved, just negicence on my side (it's mentioned explicitly on the store page).
Sorry.