" ...and let their tongues run naked into books the white and green leaves open
history theirs whose language is the sun"
kindly elucidate.
The use of the term naked here means no restraints or inhibitions. The poet wants the children to learn as much as they can and to receive quality education from Nature, without any restriction. The last line is a poetic comparison of knowledge to the sun. History only remembers the well-educated people whose language has the warmth and the strength of the sun to break the chains of prevailing norms.