Glad you asked. It is very acceptable. I lived there over a decade. Plenty of Kurdish spoken daily. It would be hard to even go a single day in public without hearing some Kurdish. What is not allowed is Kurdish as a primary language in the public education system. You can learn any language as a secondary language, but they want Turkish to be your mother tongue. Private schools can teach any language as well. A secondary language is very common in Turkey. Usually it is English.