Amazon's Alexa will be able to resurrect the voices of dead relatives, allowing users to feel as if they are speaking to lost ones beyond the grave.
The company revealed that it was working on technology that would allow its voice assistant to impersonate people with a recording of somebody's voice less than a minute long.
It displayed the feature allowing the synthetic voice of a deceased grandmother to read to her grandson. In a video displaying the technology, a child asked "Alexa, can grandma finish reading me the Wizard of Oz?".
The smart speaker acknowledged the request in its synthetic computer-generated voice before switching to a replica of the grandmother's voice.
Amazon did not say when it expects to release the feature or whether it plans to restrict how it is used.
Improvements in voice recognition have allowed companies to create increasingly life-like digital voices, creating concerns that the technology could be used to impersonate public figures or to defraud people.
"While AI can't eliminate that pain of loss, it can definitely make the memories last," Rohit Prasad, Alexa's chief scientist, said at Amazon's Re:Mars conference, where the technology was unveiled. He added that "so many of us have lost someone we love" during the pandemic.
Voices could be generated using less than a minute of audio, Prasad said, compared to hours of recording in a studio that was previously required.
Prasad said Amazon was also seeking to make the Alexa assistant more life-like so that it could exhibit "human-like common sense" and "human-like empathy".
Last year, Microsoft patented a chatbot that would be able to mimic a "past or present entity ... such as a friend, a relative, an acquaintance, a celebrity, a fictional character, a historical figure". Microsoft said this week that replicating people's voices would require strict controls and disclosures.
People have previously uploaded text message records of dead relatives to chatbot programmes, allowing them to converse with artificial intelligence imitations of lost loved ones.
One individual who recreated his fiancée using chatbot software, after she died of a rare liver disease, said the technology had both helped him find closure and re-opened old wounds, with "more of the former than the latter".
The technology is likely to lead to fears that it could be used to impersonate living people, which could be used to bypass security systems. Several banks use voice recognition as an alternative to telephone banking passwords.
In 2019, a manager at a British energy company lost almost £200,000 ($390,000) after fraudsters used artificial intelligence to fake his boss's voice, directing him to transfer the company's funds to a foreign bank account.
More than half of households in the UK have a smart speaker, according to Ofcom, with the majority owning an Amazon Echo speaker.