The speaker of this poem seems to have a pretty good grasp on classic poetry stuff like iambic pentameter and heroic couplets, meaning that he or she probably knows a fair bit about… classic poetry (kind of like Graves himself). But this person's got something to say, too. It's not just about playing with old poetic forms. Our speaker's also interested in the ways that children and adults experience the world in different ways. All in all, if you had to sum up the speaker in one word, that word would probably be "ambivalent." Good word, right? Basically, this means that the speaker has two minds about a single subject.
How can you have two minds? (Trust us, it's hilarious.) On the one hand, the speaker of this poem thinks that language can "chill the angry day" (5) and generally make our lives more comfortable. But on the other hand, the speaker thinks that language makes us "grow sea-green at last and coldly die" (11), since it also makes all of our joys a little less joyful. Importantly, the speaker doesn't come down firmly in one camp or the other. He (and we're just assuming it's a he) is really just posing a problem to us. The feeling we're left with is neither good nor bad. We're just left with a speaker who feels like he/she has figured out the difference between adult life and childhood, but even still doesn't really know how to feel about it all. Trust us—we can relate.