From the info provided by Apple on June 8:
Chinese:
New system font.
The new Chinese system font PingFang is designed for a modern appearance and crisp onscreen readability in both Traditional and Simplified Chinese.
Enhanced keyboard input.
Inputting Chinese using the keyboard has never been simpler or faster, thanks to advanced learning capabilities that quickly memorize your word choices, an improved language prediction engine that better anticipates the words you’ll type next, frequently updated vocabulary lists that contain the latest words and phrases, and a smarter candidate window that displays more character selections.
Improved trackpad handwriting.
Enter characters on the trackpad as swiftly and accurately as you do on paper — just by using your finger. A new Trackpad window reflects the proportions of your physical trackpad, gives you more room to write, and lets you write multiple characters in a row.
Japanese:
Live conversion for keyboard input.
OS X El Capitan dramatically improves the ease and speed of entering Japanese text. With an enhanced vocabulary and improved language engine, it automatically transforms Hiragana into written Japanese as you type — eliminating the need to press the space bar for individual word conversions.
New fonts.
OS X El Capitan includes four new Japanese fonts — Klee, Tsukushi A Round Gothic, Tsukushi B Round Gothic, and YuMincho +36p Kana — and more weights for the Hiragino Sans font that add personality to your documents and presentations.
Chinese:
New system font.
The new Chinese system font PingFang is designed for a modern appearance and crisp onscreen readability in both Traditional and Simplified Chinese.
Enhanced keyboard input.
Inputting Chinese using the keyboard has never been simpler or faster, thanks to advanced learning capabilities that quickly memorize your word choices, an improved language prediction engine that better anticipates the words you’ll type next, frequently updated vocabulary lists that contain the latest words and phrases, and a smarter candidate window that displays more character selections.
Improved trackpad handwriting.
Enter characters on the trackpad as swiftly and accurately as you do on paper — just by using your finger. A new Trackpad window reflects the proportions of your physical trackpad, gives you more room to write, and lets you write multiple characters in a row.
Japanese:
Live conversion for keyboard input.
OS X El Capitan dramatically improves the ease and speed of entering Japanese text. With an enhanced vocabulary and improved language engine, it automatically transforms Hiragana into written Japanese as you type — eliminating the need to press the space bar for individual word conversions.
New fonts.
OS X El Capitan includes four new Japanese fonts — Klee, Tsukushi A Round Gothic, Tsukushi B Round Gothic, and YuMincho +36p Kana — and more weights for the Hiragino Sans font that add personality to your documents and presentations.
