Consonants

The consonants of Inland Duai are as follows:
/t k b d ʔ/
/f s h/
/m n/

And of Coastal Duai:
/t k b d ʔ/
/s h/
/m n ŋ/

Inland Duai is overall more conservative, preserving the /f/ that Coastal Duai has merged into /h/; however, it is marked by a chain shift of ŋ > k > ʔ. The oldest speakers of Inland Duai preserve a backed pronunciation [q] of *k. There is no merger here; in both dialects, no stop but the glottal one can occur word-finally, and Coastal Duai has no word-initial glottal stop.

This material on Duai will abstract away from this dialectal difference by retaining both /f/ and /ŋ/ as follows:

/t k b d ʔ/ <t k b d -t>
/f s h/ <f s h>
/m n ŋ/ <m n g>

Written <f k g> correspond to Inland Duai /f ʔ k/ and Coastal Duai /h k ŋ/.

Allowed coda consonants are /ʔ f/.

Vowels with no phonemic initial are preceded by an onglide. /a/ may not appear without an initial.

Vowels

There are seven monophthongs in Duai: /a e ɤ o i ɨ u/ <a e v o i y u>.

The realization of /ɤ/ is phonetically similar to English [ʊ]. /t/ cannot appear before /i/, and /d/ is realized in that environment as a palatalized [dz]~[z]. (The distinction between alveolar and postalveolar is unimportant here, so it will not be written.)

/ɨ/ merits special comment: it is a fricated vowel that cannot appear after nasals. (Syllabic nasals could be analyzed as Nɨ, however.) It is realized as a syllabic coronal fricative after /t d s/, and as a [v]-like vowel in all other environments. It cannot appear after /h/.

Tones

There are five tones. Naturally, these are written <2 3 4 5 6>. (alternatively, -0 -l -j -x -z)

2: ˧ (mid)
3: ˩ (low, varying with low rising)
4: ˧˨ (mid falling)
5: ˥˦ (high falling)
6: ˧˦ (mid rising, varying with high rising)