I recently started my career as a French teacher, and I'm noticing lot of my students, whose mother tongue is Persian, argue on the usage of a given sentence or idiom in their native language.
For example, one says that "In Persian, we say 'xxx' when we want to speak about x concept", but someone else in the class responds with "No, we never say 'xxx' to speak about x concept".
One might tend to think that the speakers come from different social classes and use a different sociolect or come from a different generation, but all students are from the same generation and from the same social class (upper-class of Tehran).
I wonder if a paper has been written about this, or if it has a name in linguistics? Could somebody give more details about this phenomenon and the causes of it?