Bellamy is the current elder statesman in the Wales squad, and was the only player over the age of 30 to feature in Friday's impressive 2-0 win over Switzerland in Swansea.
"He is a leader by nature anyway. He's very vocal before games - he's that type anyway," said Speed.
"His ability is there for all to see but his attitude, commitment and work-rate is phenomenal.
"For the younger players to see that, someone who's been at the top for so long and still has that desire, it is massively important he does carry on."