According to Chapter 1, why is Goddess Saraswati invoked, and how is she identified with Sai Baba?

In Chapter 1 of Shri Sai Satcharitra, the author bows to Goddess Saraswati, the daughter of Brahma, asking her to make his tongue her swan and ride upon it. She is described as holding the Brahma-veena and riding a swan. The invocation is crucial because, as the text questions, without the grace of this Goddess of Speech, how could any literature be achieved? The author prays for her to be the instrument to share the nectar of Sai's life. Furthermore, Chapter 1 beautifully equates Sai with the goddess, stating that Sai himself is Goddess Saraswati, holding the Omkara-veena and singing his own life story for his devotees' salvation.