sure there is a slight difference but not really much
Once again, I tell you: listen.
There is a difference in where your tongue is in your mouth.
There is a difference in how long you speak the vowel.
I find vowel differenciation in Polish a bit tricky at times.
To an English ear, the difference is big. Say it wrong and you're in trouble.
i am still not really clear on this student thing you were trying to get at
Many people in the part of the world where I live pronounce 'stu-' as 'sc-ch-u-'.
There is the same kind of slurring with 'str' which becomes 'sc-ch-r-'
It is not what most would call proper English - foreigners shouldn't really be learning it that way,
but it is there in some regional speak.
I was once told that the Polish barred L can't be pronounced by English speakers, even though all across the southeast of England, the letter L at the end of a word or before another consonant is pronounced by many people as a W (similar to the Polish barred L).
Many assumptions are made about English pronunciation which ignore the huge variety of forms of English.