There is support learning in most Cantons.
DD and DS were both offered support, DD was 7yo and had 3 hours a day in a special non-French speakers class. DS went one morning a week, he was 4yo.
Now in our second year, DS is fairly fluent and DD not bad. She is having one extra hour a week after school.
Even the non-French speakign parents get French lessons, paid for by the Canton. I am not sure if this is available everywhere.
IMO the state schools, particularly in the small villages/towns are very good. Ours is a small school, only 90 pupils so the teacher/pupil ratio is very good. The school is very friendly, the teachers lovely and the whole community supports the school.
We had an end of year fête and the whole village was invited. The village council paid for meals for everyone, we just had to buy our own drinks. The DC paraded through the village then performed the songs that they had learned. After a few speeches (the school leavers were each presented with a digital camera as a leaving present) the children were entertained by volunteers (face painting, dressing up, craft activities) while the parents and guest drank wine coffee and relaxed. It was a great end to the year.
I think that if you come to Switzerland with an open mind (and no experience of schools elsewhere) then you will probably find the local schools good. If you have a particular idea of the kind of school you want then you might find it less satisfying.
Of course, lots of expats go for the International schools as they are on a fixed contract. I have however heard mixed reviews about the international schools too.