The slow rollout of Skype Translator began about 14 weeks ago following its creation nearly two years ago; now it's finally public for everyone.
Translator lets you converse with others who don't speak your language, translating what each of you says with text so you can both understand each other. This works with video or text chats, although far fewer languages are supported for video at the moment (more will come).
To try it out, bring up a conversation window in Skype and click the globe icon just below the call button. If you don't see it, click Help > Check for Updates in the same window.