There aren’t native Readlang mobiles app, but the Readlang web-app has been designed with phones and tablets in mind.
Tip: Save Readlang to your home screen and it will open in full screen mode just like a proper app!
I have spent hours and hours trying to import a webpage to Readlang and simply cannot get it to work on Android.
I can get it to translate words like Transover does but that is all.
Why even release this ?
The instructions I linked to above are to install the readlang.com web-app itself to your home screen. Not to import a webpage.
If you want to run the Web Reader in Android you can install the bookmarklet. I must warn you that the process is fiddly and may not work on all websites. The instructions for this are described here: Install Readlang Web Reader on Chrome for Android.
There’s also a more lightweight bookmarklet just for importing articles to read on readlang.com. See here: Install Web Importer bookmarklet
One day I hope to offer iOS and Android apps which would make it possible to integrate with the share sheet to more seamlessly send articles to Readlang. No promises on the timeframe for this though.
Currently it is not working well on my small tablet: BOOX Tab8. The reason is not related the ink flash, but is related with the screen size. When you When you turn it horizontally on this small tablet, the right sidebar is unacceptably large which makes me can not read the book and the ai analyze at the same time.
I deeply wish you consider to publish a native ios and ios tablet application. I will go to buy the new ipad mini tablet for this. 
Thanks for the feedback. I agree that the layout isn’t ideal on some screen sizes and I should work on this.