an English Part of speech question

[darkangelz5]

So this has been driving me nuts because I can't quite seem to figure it out, and it's language related... though English, so maybe I can get some help here. I'm just trying to figure out the part of speech for the word "all" in this sentence:

They are all jealous of me.

I think it's an adjective, but can you have two adjectives in row in a sentence like this? I thought it might've been an adverb too but "all" is not describing jealous, it's describing "are"...

[Viaggiatore]

I'd call it an adjective modifying "they", like "we are tall".

[rspreng]

It can be an adjective (all day) or a pronoun (I ate it all).

[Viaggiatore]

That would be an adjective too. "All" would be a pronoun in "All send their love" or "All is quiet.". In "They are all jealous" it's an adjective.