xuesen?

The other day, I was explaining something about classifiers to a classmate who teaches Chinese. I used a Chinese example to illustrate a point, and she corrected the word I used for "student" - 学生 xuesheng [ɕɥe ʂəŋ] (forgive the lack of tone marking). Instead, she told me that it should be pronounced something like [ɕɥe sɛn], like 'xue sen'. That didn't strike me as correct (especially since in order to get the hanzi above I had to type "xuesheng" into my IME). She has had no formal education in Mandarin, but is a native speaker of Taiwanese and Mandarin. My question, then, is the word she gave me a typical Taiwanese word? Or is it the Mandarin word with a Taiwanese accent? I'm a very very amateur sinologist, so I'm not really sure if I should mark this up as a sociolectal/dialectal/"dialectal"-in-the-Chinese-sense difference, lexical confusion on her part, or some combination. Tbh, I'm not too sure how mutually intelligible Taiwanese and Mandarin are, anyway. Either way, it makes me nervous about her teaching Chinese to beginning students.

Also, googling 台湾语字典 and 台语字典 gave me a bit of a headache, as my Chinese isn't that great, nor is my knowledge of Taiwanese transliterations :)

Edit: If anyone has any idea what the Taiwanese (as in, the Min Nan variant) word for student is, that'd also be very insightful