A grandfather slapped a little boy with a live frog to follow a bizarre superstition to encourage the youngster's speech development.

Footage shows the old man holding the bullfrog by its two hind legs before hitting the frantic three-year-old with it across his face in Ayutthaya province, Thailand on February 9.

The toddler Pun was was seating in the car eating snacks and a chocolate drink when his relative returned with the reptile he bought from a vendor nearby.

His family believed that slapping him with a frog would help him learn how to talk.

Relative Sabunnga Phanthu said: ‘Now Pun can speak more words. Soon he will be talking in long sentences. We believe in the many wonders of the frog.'