That's a very nice and polished site, I especially like the sidebar for reading and speaking time, that seems very useful. I notice emojis count as two characters, but that's probably the standard, right?

I think there is a large market for apps that just work, they do one thing and one thing well. I remember reading about somebody who makes a living out of their app, which is just a crossword maker, but accessible enough to be used by teachers and ordinary people.