Kalanguya is a Southern Cordilleran language spoken in northern Philippines. Like other Philippine languages, it has a voice system in which the semantic role of an argument is specified by the affix attached to the verb. The paper examines the choice of the voice type in connection with the information status of the participants involved, and looks closely into the correlation between information structure and voice alternation. It will be argued that the topicality and givenness of participants are indicated not just by NP markers but also by voice affixes. Two types of antipassive, which have been given little attention by previous works on the voice system of Philippine languages, will be proposed and explored. Through showing that different grammatical and pragmatic strategies, one of which is alternating between the antipassive and transitive, are used to signal the information status of referents, this paper highlights the importance of discourse-based analysis in studying the properties of the voice system of Philippine-type languages