According to Bandura, learning happens through Social Learning. This being said, society and the environmental factors around us play an important part on how we develop our communication techniques.
Overtime- When people live in a certain region over a period of time, the regional mannerisms that are shared by a group are brushed upon each other. Although that does not mean that the native language will be extinguished, it certainly will blend in with the language spoken by the majority. Also, certain loses may occur over time after not speaking your own native language. You may certainly lose most of the monitor language (the grammatically and mechanically correct use of language), but the linguistic corpus will remain intact unless there is no use of the native language at all.
Physical space- Depending on the mannerisms of the culture and ethnicity, traditions, and communication skills, physical space varies through cultures. The personal boundaries of every individual are used psychologically as a way to protect ourselves, or to communicate in depth. In some countries, people do not have a problem getting closer to talk to one another. In other cultures, space is key, and the more separate one is from the other the more comfortably the conversations goes. That is not to say that the space separation is extreme, just not that close together.
Socially- Social spheres like to identify themselves and separate themselves one from the other. You get this a lot with people, for example, who want to appear to be over-educated since they may want to belong to an upper class of socioeconomic nature, and for this reason they alter their intonation, vocabulary, and inflections to make themselves sound smarter, or more sophisticated. Hence, people may want to adopt a certain manner of speech to represent a certain social strata, and identify other members of such. In less educated social strata, this form of sophisticated language, excessively complicated vocabulary, and elegant mannerisms may not have a place to flourish, hence, members of that group also maintain the same manner of language usage.