StoutFiles - 8:19 pm on Feb 17, 2010 (gmt 0)
Firstly, this is a vocabulary issue not a grammar issue.
Acronyms are a type of word formation process popular in the English language. Word formation is in a sub field of linguistics, which is language structure. Language structure is grammar.
Secondly, by definition an acronym is a word and should not be spelled out when spoken.
By definition, an acronym is an abbreviation of a word or phrase. It varies because some words would sound awful if you said them as one word.
Examples of acronyms : laser & NATO
NATO is normally written in capitals because its a name (and each part would begin with a capital).
Examples of acronyms: USA, HTML, CD, CEO