As far as students' language skills are concerned, if the students cannot construct a sentence, I don't think you can expect them speak one properly. One of possibly many approaches you could take would be to have the students write a/the sentence and if constructed properly, focus then on speaking/pronunciation.
I would be interested in answers to some of the questions presented above, including identification of some of the titles of your instructional materials e.g. the "course book" to which you referred.
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