What is the difference between "or" and "either...or?
Obviously, one comprises one phonological word and the other comprises two. I have yet to find an analysis of "either...or" in which "either" is considered to be an adverb. The Summer Institute of Linguistics glossary of linguistic terms indicates that "either...or" is a correlative conjunction, which the SIL defines as "either of a pair of coordinating conjunctions used in ordered fashion." (See http://www-01.sil.org/linguistics/GlossaryOflinguisticTerms/WhatIsACorrelativeConjunction.htm ) I'm not sure that this definition makes sense for English, because "either" is not a coordinator by itself AFAIK. This definition may apply to other languages. But I've been having a hard time finding examples on the Internet.
Anyway, my chief interest is in the semantic difference between "or" and "either...or". Although I'm asking about two English coordinators, I believe that this question is appropriate for this list because other languages also have a similar contrast.
Because I'm a monolingual English speaker, examples of sentences in which "or" would be acceptable but "either...or" would not be--and vice versa--would be helpful.