Do I need to learn the local language when doing business overseas?
Like most simple questions, this one has an unfortunately complicated answer.
No, you don't have to become fluent in every market where you are buying, hiring, or travelling. As a general rule, when you are spending money people are very accommodating and flexible.
BUT, if you hoping to compete with locals, market to locals, deal with governments, build a local brand, or be accepted as a local -- then you, a partner, or a trusted HIGH LEVEL member of your team has to be fluent in the local idiomatic language.