"body of research" is all the documents and materials related to a particular line of research.  So the body of research regarding ebola would be statistics on ebola prevalence, descriptions of symptoms, analysis of treatments, etc..  "line of work" is like what your job is.  So if you are in a particular line of work, then that's the work you do, the field you work in, the industry you are in.  The high paid assassin who quits his job says "I'm not in that line of work anymore" when someone later asks him to assassinate someone.

"undergraduate courses" is appropriate.
 "Test of Oral Proficiency in English" is sufficient.  Its implied that its a language.  But "TEPOLI" looks like its a specific acronym so I think it would be appropriate to use the actual native Portuguese? definition of TEPOLI.  "grammar descriptors" is a little awkward. "grammar descriptions" feels more natural.  But I think either are okay, and "descriptors" might be called for depending on the nature of the test, I'm not sure since I don't know the test.  "which attest to the low proficiency" "graduating from education undergraduate courses" or "undergraduate courses in teaching".

Lastly, I am unsure of "of a hybrid nature", how is it of a hybrid nature?  And what exactly is it "included in"?  Do you mean "This research study is concerned with the efficacy of language testing?"  The other thing that is not clear: the Applied Linguistics studies determine low proficiency by what means?  And are they saying that that contrasts with performance on the TEPOLI?  That the TEPOLI is an inadequate measure of proficiency?  And is this research study regarding that discrepancy or is it regarding teaching methods oriented towards the TEPOLI that may be invalid?


This research study, of a hybrid nature, is included in the language testing body of research/line of work. It aims at investigating the validity of the grammar descriptors of the Test of Oral Language Proficiency in English (TEPOLI)/ Test of Oral Proficiency in English (TEPOLI), specifically designed for teachers of English as a foreign language in Brazil. The work is socially justified by the results of several studies in Applied Linguistics which attest the low proficiency level (particularly in oral skills) attained by students graduating from teacher education undergraduating/undergraduation courses and in-service teachers working in regular schools."

Please, help me

Thank you very much

Choice of words