an mp3? grammar rule?
For example when one says "what is an mp3?" he uses "an" atricle.
I read "a" atricle is put if the next word starts with a consonant sound and "an" article is put if the next word starts with a vowel sound.
Here Mp3 starts with a consonant sound M.
I wonder what is the rule which works here?
In which else situations should I put "an" article before a word starting with a consonant sound?

Question

an mp3? grammar rule?
For example when one says "what is an mp3?" he uses "an" atricle.
I read "a" atricle is put if the next word starts with a consonant sound and "an" article is put if the next word starts with a vowel sound.
Here Mp3 starts with a consonant sound M.
I wonder what is the rule which works here?
In which else situations should I put "an" article before a word starting with a consonant sound?

Answer

The reason why you write "an MP3" is not because of the letter "M" but you are actually saying "em" to say that letter.

"an em-pee three"
so you see there is a vowel sounding there as opposed to..
"a mother"

لا تفوّت فرصة تعلّم لغة جديدة وأنت مرتاح في منزلك. تصفّح مجموعتنا المختارة من مدرّسي اللغات ذوي الخبرة وسجّل في درسك الأول الآن!