The bare form palu (1b) is used to express the Undergoer Voice (UV) in Balinese. It can be analysed as having a zero prefix, represented by Ø-, on the basis of systematic formal opposition with the other forms in (1). The zero prefix is a marker prefix in the same morphological slot as other voice markers in Balinese grammar, namely, the Actor Voice (AV) prefix N-, the passive (PASS) prefix ka-...