Do's and Dont's in an interview -LANGUAGE MATTERS-problems

Hello guys this is my second post on do's and dont's in an interview.This time I am here to talk about the power of expression-the power of language.Many a time ,even in my campus ,I have seen this inability or infact a sort of inertia among students in putting forth their ideas.The problem as they say happens to be the difficulty in presenting a langauge different from their mother tongue.Its quite understandable,especially in colleges you cannot expect everytime to speak in english and naturally the tendency of inhibition in speaking comes out.This flaw mainly comes out in GDs but becomes more noticable in interview.Ofcourse you need skills to get to a job and if you have skills and still cant get the job,then the flaw must be with you language.Now how to improve your language.Mostly one can see people joining for some spoken english courses,polish their language and get through,personally I believe you can do much better without this because we remember and practice those things efficiently that we learn ourselves.I never mean such courses are bad, but I would say such courses are unnecessary especially when you are doing a graduation course or a professional course.
First lets analyse the reasons of so called "faulty" language.
Here the educational background matter most of the times( there are cases where this hasnt been a hindrance in english proficiency).Students with schooling with a regional syllabus base do face a problem as the whole portions or atleast most of them happens to be in the regional language.so they are kept aloof from the english proficiency that you would normally expect from a student who follows a CBSE or english medium,but all of them neednt be betterof with speech skills.
Next is the deliberate inertia that students show in speaking in english.There are a lot of students who just disagrees to participate in mock gds or interviews because they have to speak in english.This is mainly because of the fear of humiliation that they feel they have to face if they speak out something grammatically incorrect or if their style of speech happens to be of "low class".What they fail to understand is most of them has all learned this way and nothing is learned without mistakes.
I think these are the main problems related to the deficiency in language proficiency(If you feel there are other problems please feel free to tell me).