<p><em>Standard Indonesian/Malay</em>, <em>Melayu Papua </em>(<em>Papuan Malay) </em>and <em>Ambai </em>are Austronesian languages. Regarding Reduplication in three languages, it shows that reduplication occurs in noun, verb, adjective, adverb and numeral. The evidence shows that reduplication in numerals is only found in two languages; <em>Standard Indonesian/Malay </em>and <em>Papuan Malay. </em>Unlike <em>Standard Indonesian </em>and <em>Ambai</em>, <em>Papuan Malay </em>has three forms of reduplication: (1) full reduplication, (2) altered reduplication and (3) partial reduplication. As a result, reduplication of three languages shows that phonologically they differ in reduplication forms whereas in Optimality Theory (OT) analysis, these three languages have the same constraint; <em>FR&gt;&gt;Red=Ft</em>.</p>