In 2017, a study using the EDGE metric from species conservation found that Kavalan, although critically endangered, was among the most lexically distinct of Austronesian languages.

[3] Kavalan consists of the following speech communities ordered from north to south:[4] These speech communities in eastern Taiwan were named after older settlements from the north, such as Kariawan, Sahut, and Tamayan, where the Kavalan people originally migrated from.

Tsuchida (1985) notes that word lists collected from Lamkham 南崁 (Nankan) and Poting 埔頂 (Buding) are closest to Kavalan,[5] while Li (2001) counts them as 'Basaic' languages.

[7] In Kavalan, Proto-Austronesian phonemes have merged as follows:[8] The following Proto-Austronesian phonemes are split: The Kavalan language is also notable for having a large inventory of consonant clusters.

Kavalan affixes include: Unlike many other Formosan languages, there is no *-en suffix.