You're free to translate Kaiteki however you like, as long as it's making it possible for others to understand the app.
- Text should be informal
- Don't try to be too verbose
As Kaiteki tries to adhere to Material Design as much as possible, visit material.io/design/communication/writing on guidance on how to write.
As I'm not a native English speaker, I tend to write sentences that sound weird. It's 100% fine to submit pull requests improving the English text, as long as it's not changing its meaning.