General rule for pronouncing initialisms? [duplicate]

Possible Duplicate:
Pronouncing acronyms

Some initialisms are pronounced letter by letter, some as a word. Is there a general rule as when to use which pronunciation for acronyms that are new and don't have well established pronunciation yet?

I've seen a lot of confusion, especially in the IT world. For example WSGI — most often letters names, but it's popularly pronounced as wizz-gy or even whiskey. Of older examples SQL most often pronounced as letter names, but officially it should be pronounced sequel.

There is no general rule - strictly speaking if it can be pronounced it's an acronym. But generally computer people will try and pronounce initialisms as a joke - even if they are deliberately chosen to be unpronounceable, like fsck or wysiwyg.

SQL is an interesting special case. It is an initialism (Structured Query Language) but the original IBM language project it was based on was called SEQUEL as is the Microsoft data base product. So there is a good case for both S-Q-L and SeQueL