In fact, very few people do.

They're used only by a handful of people and all those languages are in danger of extinction.

There are more than 7,000 languages spoken in the world today.

But about a third of those have fewer than 1,000 speakers

and according to UNESCO more than 40% of those languages are in danger of extinction.

In fact, every fortnight, one of the world's languages disappears forever.

When you say dead language, many people think of Latin.

But, Latin actually never died.

It's been spoken continuously since the time of the Caesars,

but it changed very gradually over 2,000 years until it became French, Spanish, and other romance languages.

True language death happens when communities switch to other languages

and parent's stop raising their children to speak their old one.

When the last elderly speaker dies, the language is unlikely ever to be spoken fluently again.

If you look at this chart which measures the world's languages in terms of their size and their state of health,

you can see that most languages are ranked in the middle.

English, like just a few other dominant languages, is up at the top left-hand corner.

It's in a really strong state.

But if your language is down here in the bottom right-hand corner of the graph,

like Kayapulau from Indonesia or Kuruaya from Brazil, you are are in serious trouble.

In the bad, old days governments just banned languages they didn't like.

But sometimes the pressure is more subtle.

Any teenager growing up in the Soviet Union soon realized that whatever language you spoke at home, mastering Russian was going to be the key to success.

Citizens of China, including Tibetans,

as well as speakers of Shanghainese or Cantonese face similar pressure today to focus on Mandarin.

Once a language is gone, well,

it usually goes the way of the dodo.

Just one language has ever come back from the dead: Hebrew.

It was extinct for two millennia

but Jewish settlers to Palestine in the early 20th centuries spoke different languages back in Europe

and they adopted Hebrew on their arrival as their common language.

It became Israel's official language when the country was fully established in 1948 and now had seven million speakers.

Now Hebrew is the world's only fully revived language but others are trying.

Cornish spoken in southwestern England died out two centuries ago.

But today there are several hundred speakers of the revived language.

Practicality aside, human diversity is a good thing in it's own right.

Imagine going on an exciting holiday only to find that the food, clothing, buildings, the people, and yes, the language was just the same as back home.

Oliver Wendell Holmes put it well,

"Every language is a temple in which the soul of those who speak it is enshrined."

Moving that soul of the people from a temple into a museum just isn't the same thing.