In some Austronesian languages including Kelabit and Indonesian, the nasal prefix has been treated as if it is a productive and multi-functional affix. This makes the system of affixes in some languages more complicated. However, there is a main function, actor voice marking, which is seen in Proto Austronesian in light of the findings of this study and previous studies. The aim of this study is to clarify the main function of the nasal prefix N- in Kelabit. Analyzing collected Kelabit sentences, the difference between the base and prefixed form is exemplified. Here we found that the Kelabit nasal prefix N- marks actor voice by its feature of anti-passive. Before prefixation, the base, referred object, has highest prominence. To the contrary, after prefixation, the subject of the sentence becomes an actor and the referred object moves to an object position or a predicate which implies the object.
This result provides new insight into our understanding of the nasal prefix N- in Kelabit and its reflexes. Nevertheless, further consideration will be needed to yield more detailed findings about historical voice system change in Austronesian languages.