 Now let's take a look at our fricatives. As the name indicates, especially the beginning there, we have a friction going on in the vocal tract, and that's basically what we're dealing with mostly. There are a number of fricative sounds, and they're made by placing two vocal organs together and making them vibrate to a point which is audible. We have nine of these sounds, and they move from the front to the back of the vocal tract. Let's take a look here. In the front of the mouth, we have two sounds which involve our lips. Those two sounds are Pfft, and Vfft. The only difference between those two sounds is that one is voiced and the other is not. Regardless, we do involve our lips and they are the furthest front of the vocal tract with our fricatives. Again, those sounds are Pfft, and Vfft. Moving just a bit further back, we're involving our tongue and our teeth. Those are the TH sounds, and we're putting our tongue in between our teeth, and those two bits of the vocal tract are vibrating together. They're the voiced and unvoiced TH sounds, and those are Pfft, and Vfft. You can even feel the friction as it goes on. Again, those are Pfft, and Vfft sounds. Now, moving a bit further back in the mouth, we have our friction which comes from the middle of our mouth. Those sounds, we have four of them, are Sss, and Zzz. Those two sounds are made in the same manner and in the same place, and here we have an instance where again, one is voiced and the other is not. First, the unvoiced, and the voiced, Zzz. Our second set of sounds within this part of our vocal tract are Sss, and Zzz. Again, very similar sounds, same place, same manner of articulation. The only difference is that one is voiced while the other is not. Let's look at the unvoiced and the voiced, Zzz. Then, we have our sound that is into the back and that is in the glottis. It's the H, or the H sound. That aspiration becomes a lot more audible when we have what are called the glottal languages, being German to a certain extent Dutch and certainly our Arabic languages.