1. The statement is true because the group may want to maintain their speech to acquire meaning through social comparison or in relation to other groups. The members of the group may perceive their interactions with other social groups in ways that allows them to view their own group/ speech as positive and distinctive from others. When group production is language-bound, it serves to reinforce the homogeneity of the group and encourage distinctiveness. Otherwise it will be more easily available to outsiders and thus easily cross the boundaries and be adopted and adapted outside that group.
The distinction may not last very long. This is because the relationship between the language/speech and intergroup relations depend, in part, on psychological, social and situational variables including the status, size, institutional support for the group, and its language. The dominant group may respond in ways that block the development of their own language distinctiveness. Thus the members of the sub group may accept to change their situation leading to loss of distinctiveness of speech. However, distinctiveness can be heightened when members of the group competes and compares themselves with other close groups. It may however last for sometime because their language is already the established language of their interaction.
Descriptive grammar touches on the language structure since it is used by people who use English. Prescriptive grammar refers to the structure of the language as certain people think it should be used. Their difference is in the ways in which they are concerned with the rules of grammar. I am a Descriptive grammar specialist. This is because I study the rules and patterns that underlie the use of words phrases, causes and sentences and I am opposed to those who lay out rules about what they believe to be the correct or incorrect use of language.
I am in favor of a meaningful content in which language proficiency is achieved by stressing on the learning of the subject matter and not the language per se. This is because unlike the basic skills approach, it is a flexible operational framework for language instruction. It has heterogeneity of prototype models and application options for different contexts and pedagogical needs.