language acquisition by the student in a classroom setting

There are many researchers, who will say that a language cannot be learned, cannot be acquired, cannot be taken in, cannot be learned to a level of fluency that would display to native speakers of the language that the learner was of a high proficiency in the language.
I would like to retract previous statements I have made about the acquisition of language in a classroom situation. I feel now that I disagree with Lewis (2007) when he says that the target language could not be learnt to a level that would charge the learner to be' fluent'.
What is meant by and a however, in this situation, would need to be quantified to make any good judgement about the learner.

including myself, as I have said, every one who was in that class was highly motivated to succeed. And that's what we did.

N.b. please excuse any grammar mistakes you have found in this post. It is becoming increasingly more difficult for me to read and to make posts.
Thank you.

Blair.