I'm the developer of a third-party keyboard app, Snippety - Snippets Manager, which is designed for using snippets rather than regular typing.
One of my users has encountered a strange issue: after installing my keyboard (even when it is not actively in use), the predictive text bar starts showing suggestions in Polish. This happens despite the Polish language not being installed on the device. The issue resolves as soon as my keyboard is uninstalled from the system settings.
Interestingly, my application (including the keyboard) does not support the Polish language, nor is Polish specified anywhere in the app. The app was developed and published from macOS in English. This seems to be an iOS bug.
The only language-related configuration in my keyboard is the PrimaryLanguage key in the Info.plist file, which I set to "mul" because the keyboard is not intended for typing. I also tried setting it to "mis", but the issue persists.
The video presenting this issue on an iPhone 15 simulator running iOS 17.5: https://www.dropbox.com/scl/fi/xjdyucxpmv1cv0mnmwzvd/prdictive-text-issue.mp4?rlkey=aphznpdti08pz8xl84ojbyxz3&dl=0
Info.plist for my keyboard:
My project settings:
Steps to reproduce:
- Configure iOS to use English language only, with English keyboard
- Enable predictive text feature in the system
- Install Snippety keyboard
- Use the regular keyboard & start typing "dzie"
Actual result: Polish predictions appear even though the Polish language is not installed or declared by the keyboard.
Expected result: The predictive text should present predictions based on system settings.
What is even more weird, I discovered that when I add the keyboard in system settings, it automatically installs Polish language in the system settings. I even changed PrimaryLanguage to "de" (German) in Info.plist but it still installs Polish.
See: https://www.dropbox.com/scl/fi/aiv5g4z331zwy827zj47v/incorrect-language-installed.mp4?rlkey=16v5gqmb6mj8yuyyd7jwmjnsw&dl=0
Any ideas what could be wrong?
I also created a ticket: #FB13949087
I also found a similar issue from 2018 (O_O) reported here: https://stackoverflow.com/questions/53069262/ios-adds-new-preferred-language-when-installing-my-3rd-party-keyboard