Three short lines carry a quiet, aching feeling: the speaker is trying to hold on to someone who is slipping out of reach. The act at the center is small and strange. The speaker silently shapes the other person's name with their lips, as if the movement of the mouth could bring back what the mind is losing.
The last line, "What you were like," is the most telling. The speaker doesn't say they've forgotten the person's name or face. What they're losing is the person's presence, the way they felt to be around. A name is easy to spell, but a personality is much harder to recall, and the poem suggests that the name alone isn't enough.
The mood is tender and a little desperate. Nothing in the poem says why the person is gone, so the loss stays open and unexplained. The short, plain lines feel like a whisper, which fits the private, almost secret gesture the speaker describes.