Nestor,
The main issue in language is that it is based in culture. Learn a language and learn how people think. In Spanish, you can not say a bad child, you must say a badly raised child (mal criado). The fault of misbehavior rests on the parents, while in English the fault rests on the child. This is one example of how culture affects language.
The affective filter through which we process language is a issue that demands attention in that it colors the scheme of language.
The status of a language is important. French words in English are in vogue and respected, until recently, Spanish vocabulary was given a lower social status.
Gender and how language interact begs to be understood.
Age factors into when the type of language is used.
Go to www.ask.com and ask about bilingual education and you will get a bundle of variables that would pose interesting research ideas.
Posit the paper based on synthesis, evaluation, and analysis which are the highest forms of thinking.
For synthesis ask the reader to: hypothesize, combine, what if questions, modify, invent, organize, propose, plan, design, develop, imagine, create rearrange, predict, and/or improve on the topic of language.
For evaluation ask the reader to: apprise, recommend, critique, compare, solve, weigh, assess, judge, debate, criticize, rate, decide, argue, consider, relate, and/or select on the topic of language.
For analysis ask the reader to: classify, examine, separate, distinguish, investigate, contrast, subdivide, differentiate, explain, survey and/or infer about language.
Don't bore the reader with regurgitations (sp)of what you have read, make them THINK about language.
Good-luck with your thought-provoking 5 page research paper!! Asi sea....