Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.
Writefull Thesaurus - A Google Docs add-on that uses AI to give you synonyms
Mondly - Learn 33 languages in 500 bite-size lessons and 14 conversational modules.
Silicon Valley Dictionary - Urban dictionary meets Silicon Valley
MondlyAR - Learn languages in augmented reality
Reverse Dictionary - Describe a concept and get back a list of words