I built an app to help in improving English vocabulary:

https://www.woor.app/

https://apps.apple.com/us/app/woor-vocabulary/id6740453162

Initially started as small webapp to help me learn Dutch words. Made it out of the frustration that in Duolingo I cannot specify the words I want to learn and Quizlet exercising and progression felt limited. I also wanted to target the specific meanings of the words.

Then I decided to try out CapacitorJS and wrapped it into the mobile app. For now only English is available as the target language as it was easier to validate the content, but more languages are coming.

Along with it also started the podcast with language tutors about the teaching & tech. Please find the links here: https://www.woor.app/tutorandtech