Language schools and teachers may vary from Canton to Canton in Switzerland. some may have branches in many Cantons and some may not. Below is my favourite list based on feedbacks in my network:
The Most Popular Language Schools in Switzerland:
Klubschule Migros
Berlitz
Inlingua
Belingua
Alemania
Flying Teachers
ZHAW
Gemeinde courses (contact your Gemeinde web site)
Academia
Swissing