Instead, many of those born in the 2000s and later simply hold their hand flat against their head to indicate they are talking on a smartphone. “70s, 80s and 90s babies can relate,” Alvarado ...

BSL and ASL are a bit different (thumb up fist on palm upwards flat hand). ... “It is the sign he always made when he needed help,” she told Today. Advertisement.

The algorithm has been taught to recognise 21 unique hand gestures, including thumbs-up, fist, flat hand, holding up individual fingers and counting numbers.