enough, cough, plough, hiccough, although, thought, and thoroughly.

Part of the reason for that is that English has so many loan words

whose pronunciations got either maintained or approximated.

Some were written down in the way monks would spell that sound

whenever that word happened to enter the language.

Plus, French scribes from the Norman Invasion

respelled English words to match French spelling rules. Plus,

English spelling became standardized with the implementation of the printing press in

the 16th century,

which was the start of Early Modern English, but before the Great Vowel Shift.

Which was… well, a lot of our vowels shifted.

Between the confusing spelling of English,

and the fact other European languages use different letters for different sounds,

we needed something for linguists to us

to explain the pronunciation of words without having to talk face-to-face.

So in the late 19th century, the International Phonetics Association worked together

to create the beginnings of the International Phonetic Alphabet, or IPA.

A century later, and after a few revisions,

it's now used around the world by linguists,

but also phonologists, speech pathologists, singers, and loads more people.

The goal of the IPA is to have a symbol for every sound in every spoken language in the world.

Now, it does have very Eurocentric roots.

The alphabet itself is based off the Roman alphabet,

with some Greek letters thrown in.

So the closer your language is to European ones,

the more the transcriptions look like regular Latin text.

It was designed to be easy to type without needing many custom letter plates

for printing presses or typewriters,

so it also has some rotated letters and partial symbols.

And the designers didn't want to have to use a lot of diacritics;

they wanted one symbol per sound, and one sound per symbol.

And… yeah. They did it. They put every sound that humans use in speech on a chart.

When you make a sound, you push air out of your lungs

and then you cause some sort of constriction in your mouth or throat

to create that particular sound.

Two things that are really important are where in your mouth and throat that constriction is:

that's called the place of articulation,

and how much constriction you're making:

that's the manner of articulation.

The chart is organised based on those two factors.

There's also a chart for vowels,

a chart of diacritics, and a chart of extensions,

but we're going to focus on the main consonant chart for this video.

Because there's variation from dialect to dialect,

and language to language, and person to person,

the little nuances of each of those sounds

can be even further "narrowly transcribed" using diacritics.

But these are, with a few exceptions, all the consonants that humans use.

Looking at the chart, you can see some familiar symbols.

These are a great guide to help you find your way around.

We can start at the top with the plosives:

those are the sounds that you make by stopping air flow somewhere,

and then releasing it suddenly, like a mini explosion.

If you say some of the letters you recognise off the top row,

as you move left to right,

you can feel those letters moving backwards in your mouth: p, t, k.

At the end of that row is the glottal stop, which is closing off the airflow in your throat.

It happens in English when we say "uh-oh".

Depending on your accent, it also occurs in "mountain", "Hawai'i", or "butter".

The nasal line, next down, is all the sounds that you make through your nose, m, n, ng.

Then you have trills, which we don't have natively in most dialects of English,

and which I'm therefore not great at pronouncing, other than a really over-the-top [rolled r].

Then we have taps and flaps, which are like those long trills,

but a tap is the one-time equivalent.

Next are the fricatives, where two parts touch. So, s and z,

where the two parts are the tip of your tongue and the alveolar ridge,

which is the hard bit of the roof of your mouth, just behind your top teeth.

Informally, that is the “pizza ridge”,

because it's the bit you burn when you bite into pizza that's too hot.

And then finally, there are the approximants,

where two parts don't quite meet.

Lateral means that air is going round the sides,

like in l or the Welsh ll.

But: not every space in the table has a symbol.

Some of those empty spaces have white backgrounds,

and some of them are completely grayed out.

The ones with white backgrounds are possible for humans to make,

but they've not been given a symbol, because linguists have never found them

actually being used as sounds in any of the world's languages.

Sometimes they are found to exist by some researcher somewhere,

and if that happens then the International Phonetics Association will add a symbol.

The last time that happened was in 2005.

But then there are shaded areas, the shadow lands,

the sounds that are theorized to be impossible to produce.

Imagine trying to produce a sound that's in the place of your mouth

where you make a k or a g,

but using the same method that you use to go [rolled r].

You need some loose fold of tissue to make that rapid trilling,

and there's just no flesh loose enough to bounce around

right at the back of the roof of your mouth, at what's called the velum.

You could, I guess, in theory, curve your tongue back there,

but only by holding it too tense to actually make a trill.

So a velar trill is judged impossible. By all means, try it.

In the same way, if you try and cross the place of your mouth and throat

that you use to say "ha" or "uh-oh" with the method you use to make the l sound,

you're going to run into problems.

For "la" or "el" you let air escape from your mouth around the sides of your tongue: lateral.

But for "ha" you're constricting the air down in your throat at the vocal folds or glottis,

and you can't get your tongue down your throat to create that centre blockage.

I mean, your tongue has that flexibility in your mouth, 'l',

but you can't close your airway like you're making a figure 8 out of a straw,

and keep the air going round the sides.

Unless you're choking on food in exactly the wrong way,

and if you are, that's not really speaking.

A glottal lateral is judged impossible.

All those shaded boxes have the same sorts of limitations,

where it's not just that they would be difficult to pronounce, they are impossible.

Those gray boxes are forbidden from human speech,

not by choice of some High Council or the International Phonetic Association,

but just because of the limitations of being human.

Sometimes we do write things that we can't pronounce, like these:

you can't hold the letter p for that long,

or this where all those letter Es are silent!

For more on how writing is different to speaking,

my co-author Gretchen McCulloch has a new book called Because Internet,

it's available now, and there are links in the description.