Kodi is stored on your hard drive, and you can delete it all there, from your PC, but all you really have to do is remove your favourites, and you can alter your choice of language, from inside Kodi itself.
I haven't played a kodi stream, for some time, due to playback problems, instead I download, the stream, to my hard drive, and then play it when I want, without the need to be in Kodi.
To do this you go into the Kodi plugin, like The Oath, and tools, then turn on the option to download, and set your recording path, the same that you have in your hard drive, e.g. /media/hdd/movie.
Once setup, and saved, you should see a download option, on the main list of the Kodi plugin, and when you enter it you should see all your recordings. Then when you find streams, instead of pressing OK, to play it, you press the menu button and select the Download option. Not all streams allow you to download, but there are plenty that do.