opposite of algo, alguien, and siempre
A neat answer Julian but what about the case where "alguien" means "some undefined person". Is the opposite then "some defined person"?
"El premio se lo entrego a alguien", "el premio se lo entrego a mi". This can't make "mi" the opposite of "alguien" (I think) but it becomes a member of a class of opposites. My head hurts.
No criticim intended - just philosophizing.
what about the case where "alguien" means "some undefined person".
Alguien unlike in English does not mean some undefined person but some defined person
That is alguien is somebody, not anybody
So the opposite of somebody is nobody (in English it could be anybody in a negative sentence, not in Spanish)