In a clip of Nichijou that I saw, Sakamoto the cat is seen being able to talk, and appears to be quite intelligent. (His lips never move, but he does speak.)
How is Sakamoto able to do this? Are other cats able to as well?
The red scarf that Sakamoto wears allows him to talk. The scarf was "invented" by another character in the series - Hakase (which means Professor).
In another episode, a crow is wearing the scarf and can also talk.