(Reuters) – Amazon defeated claims that its Alexa voice-assistant technology infringes two patents related to speech-based digital-assistant software on Thursday in Delaware federal court.

Alexa’s technology for recognizing and responding to speech doesn’t function in the same way as the patented technology, U.S. District Judge Richard Andrews said.

Amazon and other tech companies have faced many lawsuits over virtual assistants, smart devices, and related technology. IPA Technologies Inc, a subsidiary of Canadian patent-licensing company WiLAN, owns the patents at issue, which it bought from California research institute SRI International.

IPA first sued Seattle-based Amazon in 2016, and has sued several other tech companies including Apple, Google and Microsoft for allegedly infringing its digital-assistant patents.

Andrews ruled three related patents in the case were invalid in 2019, finding they were directed to the abstract idea of “retrieving data in response to a spoken request and transmitting the retrieved data to a user.”

Amazon argued that Alexa, which responds to spoken commands and can be used to control Amazon’s smart devices, doesn’t infringe the two remaining patents because it doesn’t use the same method of communicating among “electronic agents” with an “expandable, platform-independent, inter-agent language.”

Andrews agreed Thursday, finding that Alexa’s supposed inter-agent language didn’t include the “layer of conversational protocol” that the patent describes and is a “format” instead of a “language.”

Amazon’s attorney David Hadden of Fenwick & West declined to comment, and Amazon didn’t immediately respond to a request for comment. IPA’s attorneys Paul Skiermont of Skiermont Derby and Stephen Brauerman of Bayard PA also didn’t immediately respond to a request for comment.

The case is IPA Technologies Inc v. Amazon.com Inc, U.S. District Court for the District of Delaware, No. 1:16-cv-01266.

For IPA: Paul Skiermont of Skiermont Derby, Stephen Brauerman of Bayard PA

For Amazon: David Hadden of Fenwick & West, Steven Balick of Ashby & Geddes

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