Unfair IMHO. Please remember pfm is a multinational site and terms/spellings/usage changes nation to nation.
Quite. Also, if we're going to be pedantic about these things, "Quran" is not correct either, as it doesn't follow any of the accepted rules for transcribing Arabic into English.
To elaborate:
- Arabic has 3 vowels (a, i, u) that come in long or short forms (the i and u can be also be used as semi-consonants y and w). The short forms are not written at all in modern Arabic and appear as accents in classical Arabic. In many regions the short "u" tends to be pronounced "o" and the short "i" tends towards "e". So there is some phonetic validity to the spelling Moslem (although pronouncing the "s" as a "z" is a bit of deviation).
- Arabic has a much greater variety of consonants than English. For instance, there are 2 s sounds, 2 z sounds, 2 d sounds, etc. There is a k sound that sounds like, well, k, and a sound often transcribed a q, which is halfway between a k and a glottal stop (and is extremely hard for foreigners to pronounce properly, especially when followed by an i or a u). This q sound is the one used in the Arabic word for the Muslim holy book القرآن or al-Qurʾān. Many Arabs find this q sound hard to produce too: colloquial Egyptian doesn't bother with it, replacing it with a simple glottal stop; Beduin tribes or the Sudanese often replace it with a hard g.
- In the transcription above (al-Qurʾān), the only straightforward letters are the l and the n... The short a in the article can be pronounced close to e in some regions. The a at the end is long, as in Ahhh. The "u" is for a short "u" sound (a long u would have the same bar above it as the last a). The squiggle in the middle that looks vaguely like an apostrophe is the sign for a glottal stop, which is a consonant in its own right in Arabic and absolutely essential here.
In conclusion:
- The only correct spelling is Arabic, which is not practical in other regions
- Transcriptions help, but only if you follow the system 100%. al-Qurʾān is OK. there are other ways of doing it, but Koran, Kuran, Quran are all compromised in various ways
- Either you pronounce the word in the Classical Arabic way, or you are making dialectal compromises of some sort
- Foreign words get adapted in various ways by different languages, and it's OK
- I have met many Muslims and spent many hours talking about religion with them. I have never, ever come across or heard of anybody getting offended by a botched transcription or pronunciation.