Slant rhyme, also known as half rhyme or imperfect rhyme, refers to instances where two words sound alike but do not have the same endings. This effect is usually achieved when two words have the same consonants but different vowels, but can also occur in the reverse circumstance (same vowels, different consonants). Examples of this type of rhyme can be found between the words "shape" and "leap" or "warm" and "torn." This term is dealing with situations where two words are on the edge of a perfect rhyme but fall short, containing only some partial consonance. This technique stands in contrast to perfect rhyme, which occurs when two words either have the same ending ("cave" and "save") or sound the same despite different spelling ("fly" and "high"). This technique was popularized in the early 20th century, but was used, prior to this, by Emily Dickinson and Gerard Manley Hopkins. It has since also become a common tool of contemporary singer-songwriters.
While many examples of slant rhyme exist in literature, there are a few that stand out for their subtlety and care. The first of these is perhaps the most famous: W.B. Yeats' "Sailing to Byzantium." The poem contains numerous instances of this oblique form of rhyme (which have been bolded in the following excerpt):
That is no country for old men. The young
In one another's arms, birds in the trees, —
Those dying generations—at their song,
The salmon-falls, the mackerel-crowded seas,
Fish, flesh, or fowl, commend all summer long
Whatever is begotten, born, and dies.
As the reader can see, these slant rhymes are often right next to perfect rhyme, allowing for a more subtle variation on a previous instance of rhyme. Another commonly cited example is Seamus Heaney's poem, "Digging." Below, we find the first two lines share an overt perfect rhyme but the second and third lines have a slant rhyme:
Under my window, a clean rasping sound
When the spade sinks into gravelly ground:
My father, digging. I look down
Finally, we see slant rhyme at play in the Dickinson poem as well:
“Hope” is the thing with feathers -
That perches in the soul -
And sings the tune without the words -
And never stops - at all -
The usefulness of this technique lies in its ability to subtly weave together the sound world of the poem, without the necessary obviousness of a perfect rhyme. More often than not, this catches the reader slightly off-guard as they hear the consonance of the words, but cannot identify the hidden mechanics of the sound. When close readers identify the root of this effect, it is almost like solving a linguistic puzzle. Lastly, perhaps the simplest justification for slant rhyme is its freeing of the poet's word choice. A poet is able to partially maintain their pattern of rhyme while having more room to choose different words, particularly with regard to ending lines. In the case of the Dickinson poem, this form of rhyme quiet serves the musicality of the poem without drawing attention to itself.
