Yoy is a Tai language of Thailand and Laos. The Yoy language is now in the critical endangered state due to a rapid language shift, which may eventually lead to complete language loss.
The phonology of Yoy, according to Phakkahn (2017).
Only occur in word-final position. Yoy also has six initial consonant clusters which are , , , , , and .
Some words show alternate pronunciations between the initial syllable consonants:
Yoy has two different phonemic vowel lengths. There are nine short vowels and nine long vowels. In the word-final open syllables, there is no contrast between short and long vowels, but in closed syllables and non-final open syllables, short and long vowels are distinctive.
Yoy has five phonologically distinctive tones in non-checked syllables. Checked syllables in Yoy can carry only tone 1 (mid-leveled tone), tone 2 (high-rising tone), and tone 5 (low-falling creaky).