AI-powered language learning app Speak is on a tear. Since launching in its inaugural market of South Korea in 2019, Speak has grown to over 10 million users, CEO and co-founder Connor Zwick told TechCrunch. Its user base has doubled every year for the last five years, and Speak now has customers in more than 40 countries. Keen to see Speak’s expansion continue, investors are now pledging additional cash to the startup. The company this week closed a $20 million Series B extension led by Buckley...