Hi. In the previous video I introduced you to the study of human sound systems and we distinguished between two branches of linguistics that study those. Phonology and phonetics. In this video I want to look a little bit deeper into phonetics and we will do so by considering the way in which consonants are articulated in human languages. Well, I'm not going to do that on my own. I brought my friend the spliced head here for illustration. There are three dimensions in which consonants can differ from each other. The first dimension is called the place of articulation, where in the mouth do you actually produce, the sound. One such place for instance is here at the lips. It's the place which I use when I produce sounds like puh or buh or muh. You can see it. If if you see me produce those sounds you can see that I use my lips. Puh. Buh. Muh. Such sounds are therefore called labial sounds. Labia is the Latin word for lips. Another place of articulation is right here, just behind the so-called alveolar ridge, where you put the tip of your tongue. It's the place which I use for producing sounds like tuh, or duh. Or na, or la, again you can try it for yourself. I would actually suggest stop the video now and try it. So it's ta, da, na, they're, they're produced, as I said, just behind alveolar ridge, they're therefore also called alveolar sounds. You make it by the tip of your tongue, but you can also use the body of your tongue, the, the part of your tongue which is a little bit more in the back of your mouth. If you put that back of your tongue somewhere high up, you end up here. And that's called the velar place, because that called the velan, that's the back part of your, of your mouth. Now you get sounds like kuh, guh or nah. Again, try it. Stop the video. Try it. Next to these three places, labial, alveolar and velar. English doesn't have many other places where sounds are produced. Other languages may have other places of articulation for producing sound. Maybe your language produces sounds in a very different place. I would urge you, I would invite you to go to the forum and discuss this with the other participants in this MOOC. One place of articulation which is particularly interesting is actually not visible here on the spliced head because it would be too low down. It's the one which for you use your vocal chords by doing uh, uh, uh, that is a sound which is not made in your mouth therefore but somewhere down in your throat. That is apparently another possibility. So this was the first dimension of producing sounds. The place of articulation. The second dimension is how you actually produce the sounds. What do you do to the air stream. When you speak the air typically goes out. I do it when I exhalate, that's when I speak, okay, but what do I do to this air stream coming out of my lungs? One thing I can do is just stop it, stop it temporarily and then release it again, you will hear a small explosion. Sounds like puh and tuh and cuh. All clearly have such an explosion. What do I do every time I say a puh? I close my lips completely, my air tries to go out, it gets into my mouth, then I open my lips again and you hear a small explosion. That small explosion, that's the sound of the puh. And similarly for tuh and kuh. But then at different places of articulation. So, that's one manner of articulation as it's called, they're called plosives because of the small explosion. The second manner is by closing your mouth but not completely, so that some air can slip through. Those sounds are called fricatives. Suh and fuh are good examples of such sounds. So if I say a fuh, I close my lips more or less, so some air can still get out. You hear a lot of noise. That noise is the sound of the fuh in this case. And those are the fricatives. Another interesting thing you can do is you can close the air stream in your mouth but open your nose so that the air can go out there. Muh or nuh are good examples of such sounds, they're called nasal sounds because you use the nose. You can actually see that you use the nose if you find a mirror, try to find a mirror somewhere a mirror which you can put under your nose, and then say pa, nothing happens to the mirror or say ma, and you will see air on the mirror. You will see some condensation on the mirror. A fourth manner of articulation which I would like to mention is one where you let the air go out more or less unimpeded in your mouth. Luh or ruh are good examples of that, you do something with your tongue. But the air still can get out of your mouth more or less freely. La, or ra. Again, try it, and again, think very carefully because now I mentioned these four different manners of articulation which are probably the most important ones for English namely plosives, fricatives, nasals and then the last one. Ones which are called sonorants, the ones where the air goes out completely freely. But maybe your language has different ways of producing it. But let's move to the third dimension. This is again something about the vocal chords. The things down here or here. In men you typically see them easier than in women. But you can always feel them, actually this is an exercise in feeling, put the tips of your fingers here, if you say a t several times, t, t, t, you don't feel anything, if I say a d, d, d, d. I feel, I feel it here. That's the difference. So do I use my vocal chords, do I vibrate my vocal chords. Then I say a d. Do I not vibrate them? Then I say a t. So this is the difference in voicing as we call it in linguistics. So those are the three most important dimensions in producing consonant sounds. It's the place of articulation where in the mouth that you do it. It's the manner of articulation. What you do with the air stream when it goes out. It's in voicing. In the next video, I am going to discuss these issues of phonetics a little bit more with Marten and Inge. We are going to look, for instance, at another intriguing class of sounds, the vowels.