Prime Minister Narendra Modi on Sunday said he regrets not being able to learn the world's oldest language Tamil during his long political innings as a chief minister and prime minister.

He stated this during his monthly 'Mann Ki Baat' radio address.

The prime minister said sometimes even a very small and simple question rankles the mind.

"A few days ago Aparna Reddy ji of Hyderabad asked me one such question. She said 'You have been PM for so many years and were CM for so many years. Do you ever feel that something is missing?' Modi said.

Noting that the question seemed simple but was difficult, he said, "I pondered this over and told myself that one of my shortcomings was that I could not make much effort to learn Tamil, the oldest language in the world; I could not make myself learn Tamil!"

The prime minister praised the Tamil language and its rich literature.

"It is such a beautiful language, which is popular all over the world. Many people have told me a lot about the quality of Tamil literature and the depth of the poems written in it," he said.

Modi highlighted that India is a land of many languages, which symbolise its culture and pride.