When you've got a one-word title, you're almost announcing the central theme of the poem.
We'd call it solitude, but Angelou seems pretty attached to the word "alone," so we thought we'd better stick to the real thing.
The word "alone" pops up in Lines 10, 13, 22, 25, 34, 37. Angelou makes sure that "alone" is the last word on our tongues at the end of each stanza. We're "alone" at the beginning and "alone" at the end. There's just a whole lot of words in between.