The AllSet Learning Pinyin chart is the only pinyin chart for the iPad to make full use of zooming and panning controls to make pinyin study easy and enjoyable. The interface is simple, clean, and ad-free. Every pinyin syllable has audio (just tap on a syllable to hear a native speaker recording), and toggling between the four different tones of Mandarin Chinese is easy.
More advanced students of Chinese will enjoy the pinyin chart’s support for alternate phonetic representations of Mandarin Chinese. The app comes with support for the International Phonetic Alphabet (IPA) for free, but other romanization systems like Wade-Giles, as well as alternate representations like zhuyin (used in Taiwan) are available by in-app purchase.