Studies options

Which program of study would fit this the most? Or if you've taken courses of this topic below:

Books and other resources about how different people in different areas phrase and speak and interact differently

This could include how people greet each other different, and the different ways they phrase their common greetings

This could include how people farewell each other different, and the different ways they phrase their common byes

This could include other phrasings that are more common to different areas and how they are different from other people in different areas of different things like buying at restaurants or common language usage when interacting with friends and whatnot

This could also include nonverbal communication since that would obviously be very important when it comes to understanding language meaning and related

What type of professors and scholars usually knows most about that kind of topic