Linguist Jørgen Rischel has studied the language and described its peculiarities in several works.
He divides the language into three varieties: one spoken by a small group in Laos and previously called Yumbri, and two others spoken by larger groups in Thailand.
Consonants include the two implosive stops /ɓ/ and /ɗ/, attested in words such as ɓuʔ 'slow' and ɗɤŋ 'can'.
Mlabri has a different set of consonants which occur at the ends of syllables, including aspirated sonorants /lʰ, rʰ, jʰ/.
Other final consonants are /p t c k ʔ m n ɲ ŋ h l r j w/