The new function addresses some parents' concerns that use of the technology was teaching their offspring to sound officious or even rude.

In addition, parents can now set time limits on when requests are responded to, and can block some services.

The move has been welcomed by one of Alexa's critics.

In January, the research company ChildWise published a report warning that youngsters that grew up accustomed to barking orders at Alexa, Google Assistant or some other virtual personality might become aggressive in later dealings with humans.

"This is a very positive development," research director Simon Leggett told the BBC.