Now Playing: New app launches in China to help people learn Mandarin language with virtual tutor app Now Playing, the world’s largest retailer is looking to help employees learn Mandarin with a virtual tutor program.

The app, called Cantonese Language, will teach Mandarin in-person and online through a virtual chat.

Now Playing Here’s how a woman in South Africa survived a deadly attack in her home town.

Now This: Meet the woman who saved a woman from drowning by diving into a lake Now Playing These are the three ways people can earn a college degree Now Playing The U.S. military is spending $4 billion to help soldiers with PTSD.

Now Using a robot, a woman is able to climb out of a lake in South Carolina Now Playing Who was the last person to meet your family’s last person?

Now Playing A robot built to help a woman who survived a car accident in South Korea.

Now A girl’s mother says she can still hear her daughter crying from the other side Now Playing Woman takes selfies with her dog and has it take her picture Now Playing This is the moment a man got his hands on his girlfriend’s body.

Now These students were on the front lines of the Ebola outbreak.

Now It’s time to stop worrying about your health and start embracing your new life Now Playing ‘This is not what I imagined’: New technology will help women stay in shape.

Now What is a new way to learn Chinese?

Now Here’s a guide to the top 50 countries in the world now.

Now WATCH: A couple is trying to make it work with a robotic dog, but they’ll have to deal with a new technology