Family name ใต้ (Tai 
, Sauth 
, ใต้) , around the world, is a widespread cognomen. The family name ใต้ is habitual in Macao, where it is a common surname, Hong Kong, and Cayman Islands (explore the name in all countries). Measured by absolute frequency, this name is the most popular in China, Myanmar, and Malaysia. Also, ใต้ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Tai | Myanmar, Vietnam, India, Malaysia, China |
| Sauth | Canada, United Kingdom, United States, India, Indonesia |
Southard, Southideth, and Southivong