At work yesterday we had an engineer explaining some NAC configurations and show commands. He kept saying something about the “cly” (pronounced like “cry” but with an “l” instead of “r”). I had no idea what he was talking about. But since I’m pretty clueless about NAC in general, I figured that the “cly” must be something related to NAC.
We he was done I asked one of my co-workers about the “cly”. He also had no idea. Another engineer giggled and said “I’m pretty sure that he was referring to the CLI.” The CLI is the “command line interface”, or as it’s better known “the screen”. 
I have always heard it referred to by the letters in the acronym (“See El Eye”), never as “cly”. Plus everyone knows that it should be pronounced “klee”.
I can’t really fault the guy though. In IT there are an endless number of acronyms and there is no fast and hard rule about when to just say the letters or to try to form a word from the acronym. For instance, RIP is pronounced “rip” and not “Ahr Eye Pee”. But what about DLCI? Would a neophyte know to say “Dell See” or would they sound out the letters? When I see WLSE (Wireless LAN Solution Engine) and WISM (Wireless Services Module), I see “Will See” and “Whiz Em”. I have NO idea if this is a common usage or not. It could be someday I am in the middle of an interview and I start slinging about “Whiz Em” and “Will See” and I will be the one that is being laughed at.
My rule of thumb is to sound out the letters of an acronym unless I have heard it spoken as a word. I would strongly advise not to make up a word from the acronym if you haven’t heard it referred to by that word before. I would hate to see someone undermine their credibility when speaking about “Big P” (BGP) or “Disc P” (DSCP) or Cisco “Eye Oss” (IOS). I have heard all of those terms pronounced that way. Of course, you run the same risk if you talk about the “Em Aye See” (MAC) address, but I think that at least then most people will understand what you’re talking about.
I worked with one engineer who insisted on pronouncing EIGRP as “E-Grip”. “Did you check the E-Grip neighbors?” I wanted to kill him. I understand that saying five distinct letters is pretty inefficient, but “E-Grip” didn’t make any sense. Whenever anyone tried to correct him, he stated that he had learned this from a Cisco instructor at Networkers. This may have been true, but it only meant that two people were saying it wrong. I would ask him “If EIGRP is ‘E-Grip’ then is IGRP pronounced ‘Grip’?” He did not have an answer.
