Rumours that Apple is about to expand the number of languages that Siri can speak have gathered strength based on evidence provided by the iPhone 4S' virtual assistant itself.

As Apple Insider reports, some iPhone 4S users have noticed that Siri already claims to be able to speak Japanese.

Macworld was able to replicate the claims - when asked "Which languages do you speak?", Siri replied: "I speak Japanese, English, German and French. I'm studying some new languages, too."

Siri also invited us to go to the Siri Settings menu to change the language if we wished. However, if you go to Settings, General, Siri, Language you'll find just three languages supported - three flavours of English (Australia, UK and US), French and German.

Rumours that Apple is planning to expand Siri's language support to Japanese, Mandarin and Russian as soon as March have been circulating in recent weeks after an Apple employee supposedly revealed details to a Chinese news agency.

However, Apple has only ever said that these languages will be supported at some stage in 2012, without giving specifics.

Meanwhile, Apple is reported to be covertly disabling unauthorised Siri ports on non-iPhone 4S devices, the Redmond Pie website claims.

The company is apparently cracking down on the use of Spire, a tool that enables users of jailbroken iPhone 4, iPhone 3GS, iPod touch and first-gen iPad owners to run Siri on their device.

Spire requires a server host and legitimate iPhone 4S certificate to work, something that Apple has apparently added a 'SetActivationToken' to prevent. However, a workaround for the block has apparently already been found.