This app is known all over the world. Many people try to learn a language by using Duolingo for 20 minutes a day. I can say with confidence that at this rate, you will never learn the language. If you can't afford a tutor, then try looking for apps on the internet. I remember five new idioms every night here https://sentencestack.com/. In fact, I didn't know there were so many idioms in English, so I decided I needed to know most of them. Sometimes it helps to avoid embarrassing situations.