the words are at a height,
and cannot come down,
for there is no ladder,
that can reach
This poem is about inexpression. Often a poet experiences something that they want to write about, but they cannot find the appropriate words to express it. All words and phrases they use, in some way feel lacking to themselves. This poem expresses that idea using height as a metaphor.
The poet in the poem is looking up at words. The words are at some height, and they would be otherwise able to come down to the poet, but they cannot, because there is not a ladder that can reach where they are.
The poem emphasizes the inexpression, by the ideas that the poet can see the words, the words exist, the words cannot come to the poet and the idea that the words cannot come to the poet not because there is not a ladder for them, but because there is not a ladder that can reach. The poet is in some sense standing there, looking at the words at some height, and also looking at potentially many ladders, but none of them can reach. The feeling of almost being able to connect with the words, is expressed in the poem, and emphasizes the feeling of inexpression.