The words are by the Russian poet and friend of Glinka, Nestor Kukolnik (see poem below). It is certainly not for the faint-hearted and requires heaps of practice (just look at the two cadenzas for starters!). Listen to house pianist Chenyin Li for inspiration.

There are also many interpretations on YouTube, including an impressive account by Evgeny Kissin.

Between the sky and the earth a song is heard

An unending stream of sound pours louder, louder.

Unseen is the singer in the field where sings so loudly

Above his mate the sonorous skylark.

The wind carries the song, to whom, it does not know.

She to whom it is sung, she will understand who it is from.

Pour on, my song of sweet hope

Someone remembers me and sighs furtively.