Imagine you're sitting at Starbucks in another country with your tutor trying to understand a lesson but struggling with an advanced concept. Your tutor thinks that speaking in your native language might be more comfortable to help get the concept across to you, so your brain doesn't have to translate AND try to learn something new at the same time. Seems fair, reasonable, and super helpful actually, doesn't it? Now imagine that lesson gets interrupted by someone who takes offense to the fact that you're not speaking a language they understand - even though they aren't the person you were trying to communicate with. Now imagine that person makes a whole scene about it and you'd be imagining what happened to international college student Annie An not too long ago.
The berating continued with the woman saying she hated "oriental" and that President Obama said everyone needed to speak English. A Starbucks employee came to the defense of the studying pair and tried to assure the woman that all customers may speak whatever language they want. She wasn't too pleased with that and declares that there would be trouble when she finished sending out the letter she was typing up at that moment.
Eventually, the police had to be called in after the woman refused to leave or to leave the patrons alone. She was removed.