Eastern has 300 Million speakers and includes Bahasa Indonesia and Malay, Malagasy and Taga, as well as many others.
Western has two subgroups: Polynesian and Micronesian. Micronesian includes the languages spoken by the Native Peoples of Mcronesia. Polynesian includes Samoan, Tuvaluan, Tahitian, Tongan and Hawai'ian, which are the best known. All of the said languages except Hawai'ian have official status in the countries and territories of the Pacific Ocean. Collectivly they are spoken by about 1 million people.
All Malayo-Polynesian languages tend to use reduplication to make plurals and other grammatical devices.