The software at issue is Google's Pinyin Input Method Editor (IME), which the company made available for download earlier this week. Pinyin is a romanization system for Chinese characters, and IME software allows users to enter Chinese characters by typing their Pinyin equivalents on a standard qwerty keyboard.

As users type Pinyin, the IME software draws on a dictionary of words and names to anticipate which characters the user may be looking for, and proposes possible matches.

Shortly after Google Pinyin IME's release, Chinese Internet users began to notice similarities between the dictionary used with Google's IME and a popular offering from Sohu's Sogou search engine. These similarities, in particular an error involving the name of a celebrity, were noted on a Google Labs discussion board dedicated to the company's Pinyin IME.

Several users on this and other Chinese discussion boards noted that entering the Pinyin "pinggong" into the Google IME incorrectly yields the name of Feng Gong, a popular actor and comedian. A Sohu executive could not be reached for comment, but the source confirmed that same error exists in a version of Sogou's IME.

Sogou's IME software and dictionary draw on the company's database of popular search terms to suggest names and words. As a result, Sohu has patents in several areas related to how popular Internet search terms can be used for predictive text input, which could open the door to a patent-infringement case against the U.S. search company, the source said.

A Google China spokeswoman said the company was not prepared to comment at the time of writing.