"The Voice" is all about a mysterious voice. (No big surprises there). Does the voice belong to a dead woman? Is the voice actually the wind? Is the speaker hearing voices in his head that don't exist in the real world?
Sure, this poem is about love, regret, grief, confusion, but at its heart, it may just be a poem about trying to figure out and understand our own sensations and experiences of the world. Is the voice of "The Voice" coming from inside or outside the speaker? That is the question—and the title primes us for it.