Hey there! Just wanted to give a feedback! I was looking for cheaper alternatives to LingQ, and I came across Readlang. From the first moment design and user interface really appealed to me. However, there are some things that I miss from LingQ and I though Steve might be happy to hear about that.
Firstly, I like the idea of splitting words into New, Learning, and Known categories. It always nice to come back to the new text and see that those words in yellow, that you’ve seen them before. Otherwise it feels a bit overwhelming.
Also, I had idea that even LingQ doesn’t have: To show the translation of the words that you already pressed on before by hovering over with a cursor above it. This way, I don’t need to press again, and the text look more organic. And if I ever need a reminder of the meaning, I can do it quickly hover over the words and see a small pop-up translation above it 
And thirdly, the translation of the words are not saved in the text, and I always have to press on them again, if I forgot the word.
And lastly, If I press on the word or phrase again, it will be deleted instead of shown the expalnation and I have to highlight it again which again reduces the ease of the flow.
Otherwise, amazing app and great job!
Hope my feedback will be heard and taken into consideration