Simply, "speaking in, or the language of, acronyms", including the abbreviated jargon of the particular subculture in which the acronymns develop. This results in different kinds of acronese, just like there are different languages. There are also unspoken rules of form in each subculture. So, in the IT world, TLA is a "Three Letter Acronym", but FLA is not a "Four Letter Acronym". That is too obvious, and would violate the unspoken rule that IT people are to look down and intimidate all other lesser mortals as inferior beings. So, XTLA is the proper form, an "Extended Three Letter Acronymn".
In computing acronese, the "IT Ten T" translates as "Moronic User Error". It is written as "ID10T!"
In the early acronese of letter-writing, LOL meant "lots of love". In acronese of social text messaging, it means "Laugh out Loud!" PIMP LOL means, "Pee in my pants laughing out loud!"