Songs?

Both Geena (Preeya Kalidas) and Jay (James McAvoy) sing in the movie, as do Geena's friends, and others. But during the credits it is specified that the songs that Geena sings are song by somebody else (haven't got the name here) - whereas there is no mentioning of Jay's songs, and so why I take it that he is singing his own songs. Many of Geena's songs are song i Hindi, while Jay's are only sung in English. Some of the songs are mixed Hindi/English.