There are two types of vowel harmony in Tyvan, front or back and round or unrounded. This affects the choice of vowel to use in things like suffixes. In the following chart you will see all eight vowels categorized by their distinguishing qualities. They are each followed by a set of vowels that will be "harmonic" with them. You will notice in the chart that both rounded front vowels (Ү and Ө) are followed by the same set or harmonic vowels, so the high and low quality does not affect vowel harmony.
Front: И Е Ү Ө (i, e, ü, ö) Back: Ы А У О (y, a, u, o)
Rounded: Ү Ө У О (ü, ö, u, o) Unrounded: И Е Ы А (i, e, y, a)
With so many choices of front or back and round or unround vowels, how do you know which vowel to use? Typically all vowels within a word need to be harmonic with the preceding vowel of the word. Let's take for example making the plural of the word for book, ном. Since it contains an o, and o is a back vowel, we want only back vowels. We can consider the word ном to be a "back word". Moreover, o is a rounded vowel too, so we could also say ном is a "back rounded word". Looking at the chart below, o could be followed by any of the three back vowels, А, У, or Ы. But our choice is very easy because the plural suffix uses only one of the back vowels in the list, A. As you learn the suffixes, you should study which vowels are used in front or back and round or unround forms.
ном (nom) -нар, -нер (-nar, -ner) номнар (nomnar)
|High||Ү - Е Ү||У - А У|
|Low||Ө - Е Ү||О - А У|
|High||И - Е И||Ы - А Ы|
|Low||Е - Е И||А - А Ы|