Alright, so you may be wondering how people from IGM can read English and the Roman alphabet. I mean, how stupid do I think you are, right?! Well...very. Just kidding.
People from IGM can actually read a variety of languages. It's pretty essential if they're going to be delivering to an array of planets with different alphabets and languages. They do have an "official" alphabet that they used more often in the past; it would have been under the Earth address on our envelopes (the Earth address in the Roman Alphabet so that it can be read). I don't know how it was before, when people used pigeon post and such, -- I suppose they just beamed them down. No, really, we didn't have much alien contact at the time, I've heard of some obscure tales, but I don't know which ones are true and which are not.
Each letter in the alphabet is pretty much equivalent to the letters of the Roman alphabet (seen on right, click for full size). It's malleable, however, to a variety of alphabet sounds, sort of like when we use R/r for a flat, trilled, or rolled R/r sound without changing the letter itself (Ex. English rake, Spanish flor; Japanese roku).
The alphabet began in an attempt to have a universal alphabet (being that math, the universal language, might not be ideal to send mail). The creators tried to achieve an alphabet that would look uniform and organised.
The alphabet is still in use as the "official" IGM alphabet; however, its use has declined for at least two reasons:
001. There are so many people from all over using IGM, it became difficult to even send letters back to the sender, because they couldn't read the return address, due to the fact that many people wouldn't use the IGM alphabet at all, never mind on the proper parts; andThe alphabet is therefore no longer a requirement unless the language of the sender is not among those acceptable by IGM. Most languages are, but I can't seem to get my hands on an official list at the moment. (Sorry.)
002. The alphabet proved to be a pain for those with dyslexia.