I believe that the more realistic the movie is, the more it is liked by the audience and the more it struck cords with them. Yet I have seen many movies and TV serials in both Hollywood and Bollywood alike which portray simple villagers/cowboys or otherwise illiterate characters but still somehow are shown to deliver dialogues which seem really formal and as though they are well-versed and polished with English/Hindi language words.
Example (probably one of the worst though): In 'Vivah' hindi movie, Shahid Kapoor (lead actor) doesn't have very nice Hindi, but still uses really great Hindi words after being betrothed with Amrita Rao (lead actress).
So, my question is whether the director or the script writers, while making the movie, take into consideration the way of speaking or words frequently used by such characters in real life. If not, then why not? I understand that film is made just for entertainment purposes but I am just curious.
Do they take into account the speaking style of the real life persona of the character used in the movie?