The unnamed speaker of this sonnet returns to a brook near his rural birthplace and reflects on the “sweet scenes of childhood.” Coleridge claims that he has never forgotten the intricacies of the brook and that as an adult, he can still clearly picture the brook in his mind. Coleridge further says that recalling such fond childhood memories of his rural home only make him long more for those years of carefree innocence.
In “Sonnet: To the River Otter,” Coleridge explores the most familiar themes in his poetry: the adult’s longing for childhood innocence; the connection between pastoral life and happiness, particularly childhood happiness; and the power of the imagination. In the sonnet, the speaker’s imagination transports him back to his beloved childhood memories and restores his intimacy with nature.
The words "Dear native brook!" (line 1) indicate that the speaker is remembering a stream near his childhood home, placing the poetic memory squarely in the halcyon days of youth from the outset. Although "many various-fated years have past" since he has been near this brook, the speaker still remembers it clearly and with fondness. He longs for the time he used to skip "the smooth stone along thy breast" (line 4), connecting the brook to the feminine form of nature which he sees as both nurturing and alluring. He echoes this sense of enchantment in lines 12-13, wherein the visions of childhood the brook offers "oft have...beguiled/Lone manhood's cares." While not necessarily a strong sexual image, Coleridge still leaves the hint of sexual duality in the male speaker and the female brook; he also goes another direction, invoking the nurturing spirit of Nature as mother (although the act of the child skipping stones across the brook's "breast" seems to indicate that, to the child at least, the femininity of nature is neither sexual nor maternal, but simply there).
The visions of the speaker's childhood are"so deep imprest" (line 5) that he cannot close his eyes without vividly replaying a scene from his youth near the brook within his mind's eye (lines 8-11). What stands out to him are the colors associated with the brook: the "tints" of the water (line 8), the grey willows along the side of the brook (line 9), and the "various dyes" of the sediments that have collected along the stream bed (line 10). It is the color of childhood that Coleridge wants to recall, but in all that the only color he actually names, grey, is the color of old age and melancholy. He realizes that the act of longing for one's childhood is in itself tinged with despair, for to long for youth is to admit that one no longer possesses it.
It is important to note that the speaker finds pleasure in the constancy of the features of the brook. The speaker’s admiration of this constancy could reflect his own desire that human life could possess such a constancy. During a person’s lifetime, he or she grows from being “a careless child” into dealing with “many various-fated years” as an adult.