"The Wild Swans at Coole" isn't a hard poem. The language and sentence structure are pretty simple. There is nothing super-crazy or confusing, which is helpful because we can spend more time focusing on the emotions and themes the poem attempts to describe. Now don't get us wrong. Simple language doesn't mean simple ideas. In a way, Yeats's poem is a perfect example of how something can be neat and simple, and yet still evoke powerful emotions and explore profound ideas.