 The next thing we should look at is how our consonants are arranged. For the top two rows, we have P and F at the left side of our chart and G and G at the right side of our chart. They're arranged this way because if we analyze the way we speak, we're using the front of our mouth to use these sounds as in P and F. I'm using my lips and my teeth to produce those sounds. And as we move to the right on the chart, slowly but surely we're making those sounds towards the back of our mouth. We can use the examples of G. The sound G is produced further back in our mouth than P. The next thing we'll notice about our chart is that some of our symbols are shaded. Notice that none of the symbols in the vowel sections are shaded, but only a few are in the consonant section. The shaded symbols represent what are called unvoiced phonemes. An unvoiced phoneme doesn't require any vibration in our vocal cords in order to be made, whereas with most sounds, especially all of our vowel sounds, we have a voiced phoneme in which our vocal cords are vibrating in order to produce that sound. Let's look at a few phonemes which are quite similar in the other aspects of its production, but the only difference is in whether or not it's voiced or unvoiced. Take for instance the F and V sounds. They're both made in the same way as our breath is concerned, and they're made in the same way as a placement of our vocal organs are concerned. The only difference comes in the fact that our F sound is unvoiced. And that requires no vibration in our vocal cords to be made. We can articulate this onto our students by asking them to simply place two fingers over their throat and feel the difference between F and V. You can try that at home now with the S and Z sounds. Put your fingers over your throat and pronounce the S sound and then the Z sound. You can quite literally feel the difference. The top half of our chart is concerned with the vowel sounds and it's split into two parts. On the left hand side we have our 12 pure vowels. They're one individual unit of sound and which corresponds to a vowel sound, such as a as in pat, i as in pit, or a as in pot. Within the pure vowels we have what are called long vowel sounds. They tend to be said for a bit longer than the rest of the pure vowels and we can tell our long vowels by the presence of a colon to the right of each phoneme. Secondly we have what are called the diphthongs. The diphthongs combine two vowel sounds in such a way that it's impossible to split them and still pronounce the word correctly. Our diphthongs also require a movement in the mouth in order for that vowel sound to be made. To illustrate the point let's take a look at the vowel sound oi. Oi consists of two different but distinct sounds but here they cannot be divided and still pronounce the word boy correctly. We can even see the difference when we really analyze how we're making that sound. That sound again is oi, oi. It requires a movement in the mouth in order to be made as well as all diphthongs requiring that movement in the mouth because there are actually two different sounds coming together.