What is the pronunciation of “mobile” in “mobile phone”?
Is it true that in British English it is: /ˈməubaɪl fəun/
and in American English it is: ˈ/moubəl foun/ or /ˈmoubiːl foun/
By the way, what’s the difference between the two pronunciations /foun/ and /fəun/?
Most British people say [mɛʊbaɪl], but some say [mɛʊbəl].
Most Americans say [moʊbəl], but a few say [moʊbaɪl]. I’ve never, ever heard an American say [ˈmoubiːl foun]. It seems impossible. (Anyway, Americans usually say cellphone.)
The two pronunciations of “phone” are just regional variations on the pronunciation of the vowel /o/, so I just don’t understand your question. You’ll find people in both countries who use either pronunciation.
By the way, in the US, the word “mobile” means “moveable” when pronounced [moʊbəl], but when pronounced [moʊbiːl], it means a hanging sculpture.
In the standard British and American variants, /ˈməubaɪlf_əun/ would be wrong, because the /f/ has to begin the syllable of the next word, not end the first word and leave the second word vowel-initial without a consonantal syllable onset. This is universal in native-speaker English. Either you pronounce it wrong or your transcription is buggy.
Which variants would you class as “native-speaker”? And why should one follow only native-speaker prescription? There’s a world of Englishes out there and all doing just fine.