Kayan (Kajan, Kayan proper) is a dialect cluster spoken by the Kayan people of Borneo. It is a cluster of closely related dialects with limited mutual intelligibility, and is itself part of the Kayan-Murik group of Austronesian languages.

Baram Kayan is a local trade language.^{[further explanation needed]} Bahau is part of the dialect cluster, but is not ethnically Kayan.

Glottolog v4.8 classifies the Kayan dialect cluster as follows:

The following is based on the Baram dialect:

• /r/ can be heard as either a tap [ɾ] or a trill [r] in free variation.
• /k/ can be heard as [x] when in free fluctuation with [k] in word-medial position.
• /ɲ, ŋ/ can be realized as more fronted [ɲ̟, ŋ̟] when preceding high vocoids.
• /dʒ/ may also be heard as a palatalized stop [dʲ] in free fluctuation.
• /s/ may also be heard as [ʃ] in free variation, and may also fluctuate to a stop sound [tʃ].

• Length [Vː] is said to occur in free variation or in word-final position.
• /i/ can be heard as [ɪ] in initial or medial positions, or in free variation with [i].
• /ə/ can also be heard as [ɘ] in word-medial position.
• /a/ can be heard as [ɐ] before a medial or final /ʔ/ or /h/.
• /ɔ/ can be heard as [o] when before a /ʔ/ or /h/, or in fluctuation with [ɔ].^[2]

Wikivoyage has a phrasebook for Kayan.

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