My son spends lot of time role-playing. He takes two of his toys and make them some characters and makes them talk whole day like a puppeteer. Is it normal?

It's super-duper normal. Pretend-play is one of the best games for kids (and moms too — no need to clear any mess =)) ) It is known to kindle the child's creativity, and develop his mental and oral skills. Imagine being able to create situations, obstacles and spending hours coming up with solutions and resolving problems. It also makes kids more observant of their surroundings since role play requires them to be able to come up with new situations all the time. Definitely a resounding yes for the game!