Thai Sara U

It marks a short “oo” sound, written /u/.

In กุ, ก is the consonant and ุ supplies the vowel. Keep the sound brief. This Thai u vowel does not set the syllable's tone: the consonant's tone-rule group and any tone mark also matter.

Where did this vowel sign come from?

Thai inherited it through adapting Old Khmer writing.

Old Khmer, an earlier form of Cambodian writing, descended from the Indian Brahmi writing tradition. Thai adapted that tradition to write its own sounds. The short and long u signs have antecedents in Old Khmer material from the 10th–13th centuries.

The older pronunciation is debated. A 2019 study finds limited evidence that Thai in the Sukhothai period still distinguished short and long vowels; earlier analyses interpreted spelling variation as possible loss of that distinction.

How do I type ุ?

Enter the consonant first, then the vowel sign.

Select a Thai keyboard layout; the key depends on that layout. Some Thai input systems reject invalid combinations of consonants and marks. If entry fails, test the sign after ก rather than stacking it onto other marks.