Jru' phonology

The sounds and syllable structure of Jru' are typical of the West Bahnaric languages in general. Words are mostly monosyllabic although a few words have minor pre-syllables, retaining the classic Mon-Khmer sesquisyllabic structure. The register contrast seen in other Mon-Khmer languages has not been found in Jru' and, in contrast to the surrounding prestige language, Lao, Jru' has not developed phonemic tones.

Consonants
Similar to the other Mon-Khmer languages of the region, Jru' ditinguishes five places of articulation in its consonant inventory and the stops can be either voiced, unvoiced or (unvoiced) aspirated. The consonants are given below in IPA as laid out by Jacq.

Vowels
The vowels of Jru' inherited from Proto-Mon-Khmer show three vowel heights and three tongue positions, or amount of "backness". An innovation in which Jru' developed a rounding contrast in the open-mid back vowels, results in ten vowel positions. All ten also show a length contrast, giving a total of 20 monophthongs. Unlike other languages in the Southeast Asian sprachbund, the length contrast is not between short and long, but between "regular" and "extra short".

Jru' additionally has three diphthongs, , and. The diphthongs and  are also found in certain environments as allophones of  and, respectively.

Syllable structure
The maximal monosyllable is represented as (C1)C2(R)V(C3) where C1 is any voiceless consonant, C2 is any consonant except one identical to C1 (or R if present), R is or, V is any vowel or diphthong and C3 is any consonant except a voiced or aspirated stop. The components in parentheses are not present in all words.

The maximal sesquisyllabic word structure is represented C1əC2(R)V(C3) where C1 is, or , C2 is ,  or , V is any vowel or diphthong and C3 is any consonant except a voiced or aspirated stop.