MIUI (which stands for MI User Interface and pronounced "Me You I", a play on the common abbreviation of the words user interface as UI), developed by Xiaomi, is an aftermarket firmware for cell phones based on the open-source Android operating system. It features a heavily-modified user interface that does away with the Android app drawer and has drawn comparisons with Apple's iOS. It includes additional functionality not found in stock Android, including toggles on the notification pull-down, new music, gallery, and camera apps, and an altered phone dialer that displays matching contacts as a user enters a number.
MIUI is based on Android 2.3.7 and CyanogenMod 7.1 sources, and was initially developed in the Chinese language by Chinese startup Xiaomi. Xiaomi added a number of apps to enhance the basic framework; those include MITalk (a Blackberry Messenger clone), MINotes, MIBackup, MIMusic, and MIGallery.
Updates are usually provided over-the-air every Friday. MIUI is then translated and ported in unofficial versions to other languages by independent developers. The list of translations can be found on MIUI official site.