In the first four lines of Stanza 2,"Ode on a Grecian Urn," Keats pays tribute to the imagination. How does he express this?

In the first 4 lines of stanza 2 in Ode on a Grecian Urn, Keats pays tribute to the imagination by appealing to us to "hear" with the spirit "ditties of no tone" which suggests that we 'listen' to the 95% of communication which is not spoken in our relations with other human beings and probably especially to our loved ones and try to detect what they are saying by reading the signs.