Let's settle this with a little history of the spanish distribution of Sierra On-Line games:
No Agi games were ever distributed in Spain, hence no agi games were ever officially translated into my language.
Erbe software was born in 1984 as a spanish distributor of multimedia products, centered in videogames (like Nintendo's). They had a golden age linked to the adventure games' one: they signed contracts with the most important and relevant companies of the era, distributing mostly adventure games, and in my opinion, doing very good translations. Almost every adventure game until 1994 was distributed by this company, they had contracts with LucasArts, Infogrames, Sierra; no adventure games were released without a translation.
They distributed LSL1(VGA), LSL5, LSL6, SQ1(VGA), SQ4,SQ5, KQ5, KQ6, QFG3, Police Quest 3 (PQ1 was never translated or distributed, don't know why) among others, with their respective translations. They even released cheap versions which were the EGA only ones of SQ4 or KQ5 and some more (i got this two, kq5 is somewhat damaged). Robin hood, conquest of the longbow wasn't ever distributed either.
Yet, special edition versions of some Sierra games (like SQ4 CD, KQ5CD or LSL6CD) were never released or translated (well, Gabriel Knight CD was). I guess Sierra didn't want to because they thought they wouldn't make much profit. Some of this games were later released under collections or magazines. (I got them all original in their english versions)
But then this company, Erbe, began to have internal and financial problems (which started when one of their buildings catched on fire), and little by little every partner company were leaving it alone with no products to distribute. (LucasArts signed with EA, Sierra with Coktel, Infogrames got its own distributor in Spain) So much that they wen bankrupt around 1998.
Coktel Educative (one of Sierra's subsidiaries) took care of Sierra's products around 1995, and since then they've translated, as far as I know, the following adventure games:
The Last Dinasty (translated, dubbed)
Torin's Passage (text translation only)
LSL7 (texts)
Lighthouse(texts, voices)
Gabriel Knight 3 (texts)
Urban Runner (texts)
The quality of this translations is not as good as those of Erbe's, but can be stood. They left the following games with no translation of any kind (although they did distribute all of them):
Mixed up Mother Goose
Quest for Glory 4
Shivers
Space Quest 6
Gabriel Knight 2
Phantasmagoria
Phantasmagoria 2
Rama
Shivers 2
Quest for glory 5
When the internet area started and SCI and AGI utilities were being made, the following amateur translations were made, existing one to each of the following games:
Police Quest: In Pursuit of the Death Angel (AGI)
King's Quest I (SCI)
King's Quest IV
Laura Bow: Colonel's Bequest
LSL2
LSL3
Space Quest 2
Space Quest 3
The Black Cauldron
Robin Hood: conquests of the longbow
An I think that's all.