题目内容：

阅读短文, 根据短文内容回答问题。

Let's Save Our Language Heritage

Each year on Feb 21, UNESCO holds an International Mother Language Day（IMLD）. The event is to draw attention to the disappearance of the world's languages：dozens of them are vanishing each year. UNESCO sees this as a tragedy（悲剧）, and with good reason.

What happens when a language dies out? Something huge is lost—not just sounds and marks but the way that people make sense of the world and communicate with each other. And it is through language that we have culture and tradition. Kill a language and all this is killed too.

Through IMLD, more people are becoming aware of the destruction of linguistic（语言学的）diversity in modern times and trying to stop it. Google's 2012 Endangered Languages Project is a good example. Speakers and protectors of endangered languages upload text, audio and video files to the project site. They want to introduce people to the wonders of the way that people communicate and express themselves around the world.

The Myaamia Project is a similar kind of effort. This is an attempt to revive（重新使用）the language spoken by the Miami and Illinois tribes（部落）of the US. Project members work to encourage people to study and communicate with this language, which formally died out in the 1960s.

These activities, which breathe life into languages on the verge（边缘）of extinction, might seem old-fashioned to some. But those who work to keep languages alive are not enslaved（束缚）to the past. They are enthusiastic young people who design apps and use social media to champion their activities. As the US-based social event calendar website Upcoming puts it, they“spread the word" to save the word.

So, while the problem of disappearing languages remains a very serious one, there is hope. We all have a special feeling for our mother tongue, although those of us who speak one that is not endangered might not always be aware of it. This is why we should recall（回忆）the wise words of the late president of South Africa, Nelson Mandela：“If you talk to a man in a language he understands, that goes to his head. If you talk to a man in his own language, that goes to his heart.”

1.When is International Mother Language Day?

2.What happens when a language dies out?

3.What is Google's 2012 Endangered Languages Project?

4.What can we know from Paragraph 5?

5.Why did the author mention Nelson Mandela's words?