Smaller numbers of speakers reside in the Malaysian border states, especially Kedah, Kelantan, Penang, Perlis, and Perak.

In those areas, it is the primary language of ethnic Thais and of the ethnicall- Malay people on both sides of the Thai-Malaysian border in Satun and Songkhla provinces.

Some have also emigrated to Malaysia, which offers economic opportunity but also a culture that shares Islam, which is practiced by some speakers of Southern Thai.

The majority of speakers using Southern Thai varieties display five phonemic tones (tonemes) in citation monosyllables although effects of sandhi can result in a substantially higher number of tonal allophones.

The original Thai vocabulary introduces only 11 combined consonantal patterns: All plosive sounds (besides the glottal stop /ʔ/) are unreleased.

Of the consonant letters, excluding the disused ฃ and ฅ, six (ฉ ผ ฝ ห อ ฮ) cannot be used as a final, and the other 36 are grouped as follows: ฒ ,ด, ต, ถ, ท, ธ, ศ, ษ, ส The vowels of Southern Thai are similar to those of Central Thai and, from front to back and close to open, are given in the following table.

The Thai language was introduced with Siamese incursions into the Malay Peninsula possibly starting as early as the Sukhothai Kingdom.

The words used that are etymologically Thai are often spoken in a reduced and rapid manner, making comprehension by speakers of other varieties difficult.