The many different types of acronyms/initials:
- Pronounced as a word, containing only initial letters (IE. laser: light amplification by the stimulated emission of radiation)
- Pronounced as a word, containing non-initial letters (IE. radar: radio detection and ranging)
- Pronounced as a word or names of letters, depending on speaker or context (IE. IRA: when used for Irish Republican Army, always pronounced as letters, when used for Individual Retirement Account, can be pronounced as letters or as a word)
- Pronounced as a combination of names of letters and a word (IE. CD-ROM: Compact Disc read-only memory)
- Pronounced only as the names of letters (IE. BBC: British Broadcasting Corporation)
- Pronounced as the names of letters but with a shortcut (IE. NCAA: pronounced "en cee double a" or "en cee a a", National Collegiate Athletic Association)
- Shortcut incorporated into name (IE. E³: pronounced e three, Electronic Entertainment Exposition)
- Recursive acronyms, in which the abbreviation itself is the expansion of one initial (IE. PHP: PHP Hypertext Preprocessor)
- Multi-layered acronyms (IE. JAXB: Java API for XML Binding, i.e. Java Application Programming Interface for eXtensible Markup Language Binding)
That was some hardcore wikipedia manipulating right there.