Shameless self promotion: I made an app for learning Chinese characters, Noodle Chinese [0]. It uses handwriting recognition and spaced repetition to focus on the words you need most help with. If anyone has feedback please feel free to reach out! hello@noodlechinese.com
Aside from Android support, my key suggestion would be to clearly think through on-boarding. Visiting the page, I see a $13 monthly plan, in an era of free and $5 iPhone apps. I don't know if it's any better or worse than free, so I'll pass.
On the app's page, I'd suggest clearly describing what one gets for free (before paying for a plan), so people can try it. For an app like this, I'd want to know what I'm getting before I install. Many apps just install and ask you for a credit card before anything happens. From there, I'd like to know what I'm paying for before I swipe my credit card. Clearly describing free versus paid version is key.
But my last iOS device is an iPad 2, so I don't think I can even do the free version.
However, I have no idea how to do "onboarding". You just copy-paste some text into the Chinese box at the top, and/or type characters into the decomposition keyboard in the bottom, or pick a topic from the heading row for some pre-prepared material.
I haven't got any users though, since 2017, so obviously I'm doing something wrong.
On-boarding mostly happens before users even install it:
1) Run the page by users unfamiliar with it, and see if they'd install it, why, or why not. Especially language learners (e.g. go into a Chinese classroom). DON'T tell them what it is -- users don't have you to walk you through it ("I wrote this app. I'll buy you a coffee if you tell me what you think of it....")
2) Explain what the app is on the app's page. I can't tell.
3) Definitely show a clear feature table comparing free / paid. Is it usable if I don't pay you?
4) Shoot a video showing the app in use. That's super-concrete.
4.7 stars suggests it's good. 73 ratings suggests no one is using it. Your landing page is horrible. That connects the two.
I'm also not sure about the pricing model. $80/year suggests a pretty complete course. Is that what it is?
I suspect the reason for few users is because it's relatively simple to build such an app and so you have tons of competitors, such as Pleco. For example, the visualization you have is pretty similar to a learning tool that annotates subtitles I built in 2013 - it's no longer online but you can see screenshots at https://dspace.mit.edu/bitstream/handle/1721.1/90411/Miller_... and a video at https://www.youtube.com/watch?v=3j-eXUB3eaA
What I really like about RTH over these types of apps that focus on HSK is the groupings/ordering it is presenting characters and the focus on mnemonics. I'd love an app like this that presented characters in a similar fashion.
It's an IPFS based social network, running entirely in the browser. Posts are JSON objects of content and metadata, with links to the previous post and the author's profile. Currently updates are propagated over a single pubsub channel, so it only works for real time communication. I plan to replace this with IPNS once it is implemented in js-ipfs.
[0] https://apps.apple.com/us/app/noodle-chinese/id1375293467