Testing UI translation and chat responses for AI bases application to learn languages

I created a simple language learning application (chat-based) and I need someone to test the user interface. I think a few hours, up to one day at most, should be enough.

What I would need:

- feedback on how clear and understandable the interface is for a German-speaking user

- verification whether the AI generates reasonably good responses

- checking if the speech recognition works properly

- checking if the speech synthesis works correctly

- navigating through several screens and having a short conversation with the AI in chat

- as a result: confirmation that everything works well, or suggestions for improvements

- I can provide the user interface text as a text file

- an additional advantage for the tester would be knowledge of Spanish (currently supported by the application) or another language

I will need an email address in order to add the tester to the testing list