Netflix language changes with each new episode (when I press next episode) how do I sound that?

Hi, I've had Netflix for a year and for a week the language has always been in the original language, I always echoed it in German and it changes when I'm at the new episode. How can I issue this?

ps I watch on the phone (iPhone)

Go to the Netflix website. Then go to Manage Profiles. Then select your profile and change the language or region there. Then it should work again (this is only possible on the website and not from the app).