What do we call this phenomenon of the gap between media and everyday language?

Question

In Persian, the word for nest is لانه, which is pronounced somehow as /lʌne/.

However, in everyday spoken language, people usually pronounce it as /lune/, and they usually write it as لونه.

So, considering that transliteration is common in Persian, this simple word is represented in media as:

لانه = /lʌne/ = lane

But in everyday language, people use:

لونه = /lune/ = loone or lune or loune or lone

Being a computer programmer who needs to work and extend NLP libraries, I really can't find out anything about this phenomenon. I can describe it as the gap between media/formal language and everyday language.

Do we have a scientific explanation for this? Has it been studied by linguists? What languages have bigger gaps?

Answer 1

The replacement of historic /ɒn/ by /un/ is a well-known feature of Tehran dialect (“Tehruni”), which has become the colloquial koine in the whole of Iran.

The phenomenon that you are observing is what in linguistics is called “diglossia”, where one form of the language is used in formal writing and speech, but another form is used in ordinary conversation. There is a very pronounced diglossia in Arabic, besides other languages.