The narrator's use of language is that of a teenage boy. Sammy is a typical teenage boy in many ways. He is interested in girls and is bored with his job in a grocery store. The sentence structure is simply and easily understandable, much like a teenager's voice might be. It is not bloated with long words or particularly long sentences. This adds to the realistic and believable feel of the story.
Diction means word choice; the word choice used in the story is again, typical, in many ways, of a teenage boy. There aren't any complicated, wordy passages and the diction is peppered with cynicism and romantic notions (eNotes). The imagery is also peppered with typical teenager observations if he/she were bored at his/her job and obsessed with boys/girls. Sammy describes the customers in the store as "sheep" (not a flattering comparison), and "He notes, for instance, that there are 'about twenty-seven old freeloaders' working on a sewer main up the street, and he wonders what the 'bum' in 'baggy gray pants' could possibly do with 'four giant cans of pineapple juice'." (eNotes).
"Sammy narrates this story in the first person. His voice is colloquial and intimate. His speech is informal, a factor that highlights his individuality and propensity to question authority."
Sammy is the young narrator in A & P. He is a nineteen year old checkout clerk at the A & P store. His sentence structure and diction are filled with slang expressions. He uses colorful images to describe the scene around him, such as when he describes the usual shopper in the store, a housewife, as sheep.
"His use of slang, like describing a dollar bill that had "just come from between the two smoothest scoops of vanilla I had ever known" characterize him as a fairly typical teenage boy."
He makes odd comparisons, such as when the girls come into the store, he associates them with bees, denoting the leader as the Queen.
"Shortly after that, he wonders what goes on in their minds, if it is "just a little buzz like a bee in a glass jar." Like buzzing bees, they make everyone just a little bit nervous."
One of the devices Updike uses is onomatopoeia, or the use of words that imitate the words they denote. For example, the register keys make a "bing" noise. This adds to the effect that this story, written in the first person, comes from the perspective of a teenager.
There are colloquial expressions as well. "She has a can..." (referring to the subject's posterior). No one in my part of the country (California) in this day and age would refer to that portion of the body as a "can". There are other example's as well.
Updike uses many metaphors, besides "can", to refer to body parts: cresents, moons, etc..
Many sentences appear to be phrases which add to the stream of conscience (spelling is wrong here) and quick pace reading.