Siri, the personal assistant software on the iPhone 4S, may have given clues about upcoming features. When asked which languages Siri speaks, she replies that she speaks English, French, German, and Japanese, and that the languages can be changed in the iPhone’s settings app.

What’s interesting, though, is that when you actually go to Siri’s languages settings on your phone, Japanese isn’t on the list. There’s French, German, and three dialects of English (American, British, and Australian), but no Japanese:

While it could be some sort of glitch, it seems likely that the response means that Siri will be getting Japanese support. Apple’s FAQ page on Siri promises support for Japanese, Chinese, Korean, Italian, and Spanish coming later this year. If this isn’t a glitch, then it looks like Japanese support will be coming soon – possibly with iOS 5.1, which should release around the same time as the iPad 3 launches. There are no hints yet of when support for the other four languages will follow.

When the iPhone 4S launched in October with Siri, language support was somewhat lacking. While English, French, and German are among the world’s most common languages, they are still only three among hundreds. To make matters worse, Siri has a notoriously hard time with accents. The software is optimized for native accents, and speaking a supported language with a foreign accent – say, Scottish – can create all kinds of trouble. The addition of Japanese support will hopefully open Siri up to a wider range of iPhone 4S users than before.