Dave Bonta's "Slight difference" starts with a small misreading: the speaker sees "word" and reads "world." Only one letter separates them, the "l," which the poem calls a "ledge." That image makes the letter feel like a tiny shelf where meaning could perch, or slip off.
The final two lines give the poem its feeling. The gap between the two words is compared to "the interstice between / the swallow and the air." A swallow moves through air so quickly and closely that it seems almost part of it, yet the two remain distinct. In the same way, language hugs the world without quite becoming it.
The speaker sounds quietly wondering rather than troubled. The mistake is treated as a small, pleasing insight, not an error to fix. The mood is light, airy and observant, as if the poem itself is skimming along the edge of what words can hold.