Perfect for learning languages
I am a teacher who has also learned new languages for myself. I would like to point out that this app does not mention a unique feature of their keyboard that I found extremely useful: when you write in a foreign language and make grammar / enhancement corrections with QuickFix, it suggests new words and phrases that you begin to learn on a subconscious level. My English proficiency isn't high, but after a few weeks of using this app, I grew very comfortable messaging my friends in English. Furthermore, I found myself using these new words when speaking to them. It's incredible how quickly I started doing this because of this app. I believe the main insight here is that this keyboard is accessible in any messaging app without needing to switch. Therefore, you use it continuously, allowing your brain to immerse itself in the text you have written, hence memorizing new phrases added by the app more quickly.