Onomatopoeia refers to a word that phonetically evokes the noise that it describes. (Examples are “buzz,” “bubble,” and “rattle.”) With slight variations, “pocketa-pocketa-pocketa” recurs frequently in Mitty’s fantasy life and is always associated with machinery. In each case, the sound introduces an element of danger: the overtaxed cylinders of the Navy hydroplane; the faltering anesthetizer in the operating room; the “menacing” flamethrowers in the cratered hellscape of WWI. This sound, which has lodged in Mitty’s unconscious during his drive to Waterbury, is probably that of his automobile. So, a rattling noise that vexes him (on a trip he does not want to make) becomes, in his daydreams, a harbinger of doom, which he quickly neutralizes through his legendary decisiveness and expertise. However, this literary device also serves a humorous role, showing the limits of Mitty’s imaginative riffs: Again and again, like a child at play, he returns to this same sound effect.

Jargon is the technical language peculiar to a certain profession, phenomenon, or field of study. In Mitty’s daydreams, his inept use of jargon subtly lampoons his efforts to lend both verisimilitude to his pipedreams and an aura of prowess to his various heroic personae.