SAN FRANCISCO — Google will introduce its much-anticipated entry into the voice-activated home device market on Wednesday, according to people who spoke on the condition of anonymity.

Named Google Home, the device is a virtual agent that answers simple questions and carries out basic tasks. It is to be announced at Google’s annual developers’ conference in Silicon Valley.

Google Home will come to market in the fall — a long time away, given the speed of technology, but Google needed to plant a stake in the ground now. The device will compete with Amazon’s Echo, which was introduced less than two years ago. Amazon has already sold an estimated three million units.