Symmetrical voice

Symmetrical voice, also known as Austronesian alignment, the Philippine-type voice system or the Austronesian focus system, is a typologically unusual kind of morphosyntactic alignment in which "one argument can be marked as having a special relationship to the verb".^[1] This special relationship manifests itself as a voice affix on the verb that corresponds to the syntactic role of a noun within the clause, that is either marked for a particular grammatical case or is found in a privileged structural position within the clause or both.

Symmetrical voice is best known from the languages of the Philippines, but is also found in Taiwan's Formosan languages, as well as in northern Borneo, northern Sulawesi, and Madagascar, and has been reconstructed for the ancestral Proto-Austronesian language. In the rest of the Malayo-Polynesian languages, including Proto-Oceanic, symmetrical voice was lost almost entirely.^[2]