How do I compare and contrast the tones of these three poems from Langston Hughes: I, Too, Negro Speaks of Rivers, and Theme for English B?
I need to discuss the tone of each of the three poems but I don't know how to begin...
One of the critical elements of tone in each of these poems is the articulation of what it means to live in an America that possesses challenges in fulfilling its promises to all of its citizens. In these poems, I would pay attention to the words and lines which indicate that there is a gap between what has been professed and what is delivered. For example, in "I, Too," the idea of being told to eat in the kitchen with the reference of "the darker brother" helps develop the mood that something is being denied that was originally promised. The mood present in all of these works is to make a statement on what it means to be Black in America, the hyphenated American's identity, and exploring the notion that there are individuals who live their lives waiting for delivery of what was previously promised to them.
I agree with what the previous poster says, but I would encourage you to begin answering your question by defining the word "tone" for your own purposes. "Tone" is not the same as "theme," for example; all three poems can indeed be read as addressing the black person's place in contemporary society, but the poems differ significantly in tone. You will probably want to look up defnitions of the term "tone" in several sources and pay paticular attention to key words in the different definitions.
For example, one internet source, cited first below, defines tone as "the author’s attitude, stated or implied, toward a subject. Some possible attitudes are pessimism, optimism, earnestness, seriousness, bitterness, humorous, and joyful. An author’s tone can be revealed through choice of words and details." A second internet source, cited second below, defines tone as "the author’s implicit attitude toward the reader or the people, places, and events in a work as revealed by the elements of the author’s style. Tone may be characterized as serious or ironic, sad or happy, private or public, angry or affectionate, bitter or nostalgic, or any other attitudes and feelings that human beings experience. See also style."
In comparing these definitions, you may note several key terms: "attitude" is used in both definitions but "style" is only used in one. One definition uses the words "stated or implied" while the other only uses the word "implicit" (which means pretty much the same as "implied"). While terms in these definitions do overlap, the two definitions are not identical. You may find one definition more useful than the other for answering your questions. (Of course, you may also find other, perhaps superior definitions of the term "tone.")
At this point, you can rephrase your initial question to read: How does the attitude of the speaker differ in these three poems? or How does the speaking style of the speaker differ in the three poems?
Here are some initial, quick comments and observations that may get you started:
On attitude: There seems to me to be some "attitude" (in the sense of sassiness or spirit) in the "I, Too" (especially in the final lines of the poem) and perhaps even more in "Theme for English B." In comparison to those poems, "The Negro Speaks of Rivers" seems to have a very somber or serious tone.
On style: The grammar and word choice of "The Negro Speaks of Rivers" seems to me the most formal of the three. There's no slang or colloquial speech in this poem. To me, this poem also seems the most highly structured. It's about as close as Hughes gets to writing formal poetry.
These observations lead me to think that we can place these poems on a scale from serious to playful (or from sombre to sassy, if you prefer), with "The Negro Speaks of Rivers" on the serious side, "Theme for English B" on the playful side, and "I, Too" somewhere in between. To support such a placement, of course, we should reread each poem carefully and be ready to present evidence from each poem (e.g. specific words or phrases, grammar, direct or indirect expressions of the speaker's views, etc.).