I've noticed that some people in my office spell out "data import tool" as D. I. T., whereas others will say "dit" (like "ditty"). Is trying to pronounce an acronym as a word, as opposed to spelling it out, ever correct?
All I could find on pronouncing acronyms and initialisms is this list.
The list distinguishes between acronyms and initialisms. Basically, acronyms are abbreviations that are pronounced as a single word and initialisms are an abbreviations, that are pronounced as a series of letters From this wiki article.
It is just a matter of preference.
There is a list of acronyms and initialisms available on wikipedia here - http://en.wikipedia.org/wiki/List_of_acronyms_and_initialisms
You can observe that acronyms and initialisms are marked out based on general usage.
However, there are some examples like DITY (unfortunately, DIT is not on the list) or ROD or URL or RAP and many more which are categorized as either an acronym or an initialism.
Hence, it is up to the group to decide whether to use DIT as an acronym, an initialism or both based on the convenience and succinctness required.
Acronyms are only acronyms if they can be pronounced as a single word i.e. NATO or sonar, or radar.
Abbreviations differ in that they are pronounced separately, as in FBI, or ATM or HIV, etc.
So your question is:
Acronyms should be pronounced as a word, not spelled out. The thin blue line, is , when is an abbreviation an acronym?
But otherwise, acronyms are pronounced as a word.
The difference here is between an acronym, which is an abbreviation using the first one or to letters of a longer term pronounced as a word, and an initialism, where a similar set of letters is spelled out.
Whether an abbreviated term becomes an initialism or an acronym is totally dependent on common usage, which is in turn dependent on the culture, which can be as localized as two people using it in conversation. As long a the two people talking understand the term as it's being said, they're communicating effectively and there's nothing "wrong" about how they say it.
Abbreviations are generally pronounced as acronyms whenever the term has been designed to mimic a dictionary word (e.g. D.A.R.E. - Drug Abuse Resistance Education), or when there exists a relatively common, logical pronunciation for the abbreviation, e.g. SQL (pronounced like "sequel"). These are the ambiguious ones, as most of then started as jargon and passed into relatively common usage. For instance, the layout files created when programming using the Microsoft Windows Presentation Foundation are known as "XAML" files. Those "in the know" generally pronounce the term "zhamul"/"shamul", but this pronunciation must be learned and is thus restricted to those who use the technology, making it jargon.
Abbreviations are usually pronounced as initialisms either when an acronym is not well known in a group (XAML or SQL often are spelled out the first few times they're used), and/or when there's no good way to turn it into a word. A lot of governmental agencies and military units/divisions are known by initialisms; FBI, ATF, USAF, DHS, SAS, OSS. Executive positions are also commonly spelled out as initialisms: CEO, COO, CFO, CIO, etc.
As you can see, no hard and fast rules other than what sounds right. Military abbreviations are a prime example: the HMMW-V is pronounced "Hum-vee", and top-brass designations like CINCLANTFLT and CINCPACFLT are pronounced as words, but there's nust no good way to pronounce USMC than to spell it out (or just say "the Corps" or "the Marines").