If a student studied in English (the medium of instruction was English), but in a non-English speaking country, he / she would still need to obtain another proof of language proficiency.
Given that information, you should be able to find out yourself, whether you need a certificate that proves your proficiency in English, e.g. an IELTS or TOEFL.
Once again (since we still receive this question very often):
In case you've studied in a non-English speaking country, it is not sufficient to provide a certificate, which states that your "medium of instruction was English".