Okay, it would be a short video if I just gave that one answer.

But that's the number according to the 2020 edition of Ethnologue,

widely considered to be the closest thing we have to a directory of languages.

But here's the catch: languages are not separate, distinct things.

They evolve, split, merge, fall out of use.

And it's often difficult to say exactly where one language ends, and another begins.

Sure, it's clear that my English and another person's Mandarin

are completely different languages,

but what about my English and someone else's Scots?

Or someone else's Singlish?

Or someone else's rural Southern American English,

which might not be understood by the Dowager of Downton Abbey?

And it's not just about location, either.

There's a difference between the English I use here,

versus what I actually use when I'm talking to friends.

And what about over time?

Where does English start to become Middle English or Old English?

At some point, it's different enough to get a new label:

but there isn't a naturally-occuring clean line.

There's an old saying that a language is just a dialect with an army and a navy.

Languages change to adapt to the needs of their speakers.

And there are a few reasons for that.

Maybe it's to provide new words for new concepts.

“Computer” used to be the term for someone who was paid to sit and do calculations.

Their job was to compute, they were a computer.

When automated tools came along, they took on the name.

Sometimes languages change to speed up communication.

“Going to” wasn't always a marker for future tense:

and saying “I'm going to start” makes no sense when taken literally.

You can't go to “start”, start is not a place,

but the phrase “going to” became lexicalized.

And then it turned into a word: “gonna”,

and then “I'm gonna” became “Imma”.

That's a word in common use that's probably under fifty years old. Still English.

Sometimes a language changes because people are trying to find an identity.

The words we use help us fit in or to stand out.

Language changes spread across populations,

they act as markers of who you are and who your group is.

If enough people change their pronunciation, intonation, their word and grammar choices, all together,

you end up with a dialect.

If that happens over and over and over for centuries, well,

you might end up with a new language.

Or you might end up with an old one falling out of use.

Centuries of colonialism and globalization have encouraged the death of local languages.

And even fairly major ones can be in trouble.

Icelandic is spoken by more than 300,000 people,

it's the national language of a European country.

But it's not supported by iPhones or Android phones

If you speak Icelandic and you want to use a smartphone,

so if you want to participate in modern life,

you need to speak another language, probably English.

Very little media is translated into Icelandic,

almost no-one who moves to Iceland speaks it,

which means that Icelandic youth sometimes

just use English between each other as a first language.

Unless deliberate efforts are made to keep it alive,

even a national language like Icelandic could be at risk eventually.

So, yes, Ethnologue counts 7,000 languages,

based on fairly reasonable lines that they've decided on.

Someone has to draw some lines somewhere, so they do.

But of those 7,000, 50% to 90% of them may be functionally extinct by the end of the century.

And while I'm sure there would be advantages to one global language,

it's not just about communication:

it's about access to culture, to history, to subtext,

to the insights that can come from one language explaining in a single word

what would take another language fifty.

If you're watching this and thinking “ah, it doesn't matter too much”,

imagine how you'd feel if it was English that was endangered,

and ask yourself if you'd be okay with the next generations

only having translations of the works you grew up with.

If you want more linguistics, then my co-author Gretchen McCulloch

has a podcast called Lingthusiasm.

The link is in the description, I recommend it.