Amazon trained Alexa in secret by hiring unsuspecting people to ask questions in a room filled with hidden prototypes

• The Amazon Echo was an ambitious project for the company and took years to create.
• Author Brad Stone broke down how Amazon created Alexa in his new book.
• The company collected speech data from thousands of workers while keeping the project a secret.

Amazon quietly laid the groundwork to eventually leapfrog Google and Apple in the virtual-assistant race by secretly collecting data on speech patterns from thousands of unsuspecting workers, a new book reveals.

When the idea behind the Amazon Echo was first pitched in 2011, executives expressed doubt.

"This is going to be hard," Amazon's senior vice president of device, Dave Limp, told Insider's Eugene Kim he recalled thinking at the time. "It foretold a magical experience. But it would require a lot of inventions."

The device was stuck in Amazon laboratories for years before the company had a major breakthrough and launched the program that made Alexa "smart." Author Brad Stone broke down the process of how Amazon created Alexa in his new book "Amazon Unbound: Jeff Bezos and the Invention of a Global Empire."

"Internal testing with Amazon employees was too limited," Stone wrote. "They would need to massively expand the Alexa beta while somehow still keeping it a secret from the outside world."

In 2013, the team tasked with developing the Amazon Echo launched a data-collection program in partnership with the outside firm Appen, Stone reports. Appen rented out homes and apartments in Boston and filled the rooms with different kinds of electronics, from microphones and TVs to tablets and gaming consoles, according to the book.

Meanwhile, they hid around twenty early versions of the Amazon Echo throughout the rooms. A spokesperson for Appen was not immediately available for comment.

Temporary contract workers were then paid to walk through the rooms, reading scripted questions from tablets. Stone said the scripts asked participants to ask "open-ended requests." The Echo speakers were off, so Alexa did not respond to the requests, but collected the data and sent it back to a team of Amazon employees who broke the requests down into specific queries that Alexa could easily understand.

The process was repeated six days a week for six months, according to Stone. The data-collection process was so successful that Amazon expanded into 10 other cities.

"It was a mushroom-cloud explosion of data about device placement, acoustic environments, background noise, regional accents, and all the gloriously random ways a human being might phrase a simple request to hear the weather, for example, or play a Justin Timberlake hit," Stone wrote.

The program was not without its struggles. Stone said neighbors at the various locations would often get suspicious of the people going in and out of the residential locations. At one point, a neighbor in Boston called the cops concerned that the residence was being used as a drug-dealing or prostitution ring. The police were shown around the house and the location was quickly shut down after they left, according to Stone.

Some of the contract workers themselves were even suspicious of the program, he reported. There were often instances when the workers would refuse the job immediately after seeing the setup of the rooms. Others mocked the program.

"One Amazon employee who was annotating transcripts later recalled hearing a temp worker interrupt a session and whisper to whoever he suspected was listening: 'This is dumb. The company behind this should be embarrassed,'" Stone wrote.

But Amazon's covert project was far from a waste, about a year later the Amazon Echo was released and eventually became a major hit for the company.

Through Alexa's savvy, the company was able to overtake Apple and Google in the virtual assistant space, even though Siri was released three years before the Amazon Echo. In 2019, the Amazon Echo accounted for the largest portion of the global smart speaker market share at 31.7%, according to consumer electronics research expert Lionel Sujay Vailshery.

An Amazon spokesperson did not immediately respond to a request for comment.