“Daddy” doesn’t have a set rhyme scheme. Even so, Plath uses rhyme to powerful effect. Perhaps the first thing a reader notices about the poem’s rhyme scheme is the preponderance of lines that end with the same “ooh” sound. Indeed, nearly half of all lines in the poem end with this sound. For example: do (line 1), shoe (2), Achoo (5), you (6), blue (12), du (15), and so on. These “ooh” sounds establish what we might call a “sonic signature,” which we hear constantly as the poem proceeds. Many of the rhyme words listed above repeat frequently, and often in close proximity to each other, creating what’s known as identical rhyme. A prominent example of identical rhyme appears in lines 31–35:

     An engine, an engine
     Chuffing me off like a Jew.
     A Jew to Dachau, Auschwitz, Belsen.   
     I began to talk like a Jew.
     I think I may well be a Jew.

In this passage, the signature “ooh” sounds underscore the speaker’s controversial identification as a Jew, which is one of the poem’s central tropes.