Currently on my iPhone (current iOS, but this has been an issue since long ago), the keyboard language switches randomly between English and Chinese, every time I go to a new app or an input field.
There doesn't seem to be a pattern, like what was the input language when I last used the app. Sometimes it appears to switch to a different language even for the same app (e.g. Safari) when I switch somewhere else and switch back. I have 3 input languages installed: English, Simplified Chinese and Emoji. Though the input never defaults to Emoji.
Any idea what is going on? Are there any fixes?