Social class can also signify belonging to certain social castes as in India. In these societies, language use is determined by the social caste that one belongs to. In this instance, the thought of social mobility by change in language use is hardly thinkable (completely opposite of the case of the Texan in New York).
Language use can also be used as a means of social prejudice. In fact, many people believe the SBE (standard British English) or RP (received pronunciation) is 'better' English than other dialects. This results in certain prejudices against people who are not proficient in RP. At times, people who are not proficient in RP strive to acquire RP in order to bring about the very real social advantages attached to its use. Currently in the USA, there is hot debate as to whether AAVE (African American Venacular English) should be allowed in the classroom. Many people feel that this form of English is inferior and should not be allowed others argue that it is equally valid and should therefore be allowed. Personally, I feel that the economic reality of the situation would suggest that, while AAVE is perfectly valid as a language, it might be better for an individual to focus on what is accepted as good English in the USA. A possible solution to this problem might be that all written and reading work be done in 'standard US English', but that discussion be allowed in AAVE. It is however, a very difficult decision because of the validity of AAVE contrasting with the very real socio-economic advantages of speaking 'standard US English'.