Google has turned on support for thousands of characters that enable indexing algorithms to find documents that previous searches may not have found. Google does this through Unicode.
Mark Davis explains Unicode, why it's important and how it works. He also writes that Google can support nearly half the Web's information through Unicode, though Web pages can rely on a variety of other character codes, such as ASCII, Latin-1, or Windows 1252. Most encodings represents a few languages, but Unicode can represent thousands, from Arabic to Chinese to Zulu.