Ylysepen has 9 vowels. Each front vowel has a back counterpart, each close vowel has a mid counterpart, and each unrounded vowel has a rounded counterpart. The only exception is "a" which has none.
| Front | Back | |
|---|---|---|
| Close | i • y | ɯ • u |
| Mid | e • ø | ʌ • o |
| Open | a | |
Most vowels are represented by one sound. A few can be represented in multiple ways depending on context.
| Phoneme | Letter(s) | Examples |
|---|---|---|
| i | é • i | kim, énur |
| y | y | yly, kyg̈ |
| ɯ | w | owre, lwken |
| u | u | um, uabl |
| e | á • e | tenerát, njámju |
| ø | o̧ | o̧s, korgo̧ |
| ʌ | u • e • a | kurgis, tjikle, talura |
| o | o | koner, owre |
| a | a | saa, zvaren |