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.

Team Time Zone - Local clocks for distributed teams who use Slack

LanguageBeast.com - Study English synonyms and antonyms to enrich your vocabulary

Every Time Zone - Online tool for keeping up with times around the world.

Babble - A more personalized social network

Timezone.io - Keep track where and when your team is.