Apple’s know-it-all voice-operated assistant Siri is in more legal trouble after a Taiwanese university launched a patent infringement lawsuit against it in a Texas court.

Taiwan’s National Cheng Kung University is alleging that the iPhone service infringes two voice-to-text patents granted to it in the US in 2007 and 2010.

Yama Chen, legal manager at the university, told Reuters that the lawsuit was filed in the US District Court for the Eastern District of Texas because cases get seen quickly, rulings are usually in favour of patent holders and compensation is higher.

The uni isn’t saying how much it wants in compensation but is apparently calculating based on US sales of Siri-enabled devices – effectively all iPhone 4S handsets.

It's also looking at whether voice recognition tech from Microsoft and Google may also have infringed its patents

The voice assistant technology which Apple acquired back in 2010 has already managed to embroil the firm in several legal disputes.

It was hit with two class action lawsuits in the US over alleged misleading ads which made the electronic PA seem more intelligent and quick-witted than it actually is.

Over in China, meanwhile, a Shanghai-based developer of voice assistant technology is claiming Siri infringes a patent it holds for a "type of IM chat bot system" dubbed Xiaoi Bot, which was approved back in 2006.

Siri can’t officially speak Mandarin or Cantonese yet, of course, although the capabilities were unveiled at this year’s WWDC. Users in the region will have to wait for iOS6 before they can see what all the fuss is about.

In the meantime, Apple’s lawyers will be enjoying the continued wealth and work which the voice-operated assistant is providing for them. ®