Absolutely provided the student is well versed in the subject area of research or is willing to learn concepts fast. Certainly the student might need considerable assistance when writing the final dissertation, however, should be able to collect and analyze data as accurately as someone whose native language is English
I think supervision is easily done since English is used as a means of expression. The foreign student should be competent in English and very familiar with the research topic he is writing about. I have the experience of supervising many international students whose language differs from my mother tongue.
My father as a Professor of Sanskrit has successfully supervised two foreign Ph.D. students (belonging to Thailand) who were neither fluent in Indian language Hindi nor in English.
That’s why English Language Universities has English Language Requirements IELTS 7 band above or TOFEL 550 above. A student less score than that score Not granting admission. I would suggest no problem if student is good score in IELTS or TOFEL. Regards