Teachers at GIS (international stream) speak native english.
My son is in GIS' pn class and will move to another international kindy for K1 (with priority for P1 entry under the same system) the coming sept. Considering his lack of explosure to english at home, his proficiency is good.
It is a happy school focus on holistic development of kids. Staff/teacher are all very nice and helpful.
Definitely not that type of school with main emphasis on academic.
Its really up to you, of what you want for your child.