Vowels. Principles of Classification.

1. Stability of Articulation:

1. Monophthongs:

2. Diphthongs:

3. Diphthongoids:

4. Triphthongs:

2. Tongue Position:

1. Front;

2. Front-retracted;

3. Central;

4. Back;

5. Back-advanced;

6. Open;

7. Close;

8. Mid.

3. Lip Position:

1) Rounded;

2) Unrounded.

4. Character of Vowel End:

1) Checked;

2) Free.