[bread_baker]

English has more vowel sounds than some other languages do. It could be that your student's language does not have some of the sounds of English. That could be the reason why your student is struggling - the sounds are new and foreign.
When I taught pronunciation, I taught the sounds of short vowels and long vowels and consonants. I taught the students to break apart words. Example: pen has 3 letters and 3 sounds. I taught them to make each sound and then put the word together.