The selfish giant

sundarnaz"For his own conversation was limited." Does it mean he used to talk less?

Could you provide more context?

One day the giant came back. He had been to visit his friend the Cornish Ogre, and had stayed with him for seven years. After the seven years were over he had said all that he had to say, FOR HIS CONVERSATION WAS LIMITED, he determined to return to his own castle.

His ability to make conversation was limited; for example, he had knowledge of or interest in only a small number of topics, or he just didn't much like chatting. Mind you, seven years would exhaust many people's topics of conversation!

Structurally the sentence is slightly faulty, though this does not affect your question.

GPYhe had knowledge of or interest in only a small number of topics

The castle had no Internet connection, so his knowledge, and topics on which he could converse had their limits.