David Mamet is famous for his attention to detail in dialogue. All the characters in Glengarry Glen Ross have very specific speech patterns. Words are often left out of sentences, and the grammar, though rarely "proper," always makes intuitive sense. For example, Mamet will have a character say "should of" instead of the grammatically correct "should have," because, first and foremost, Mamet is trying to reflect the way he believes his characters would actually talk. Moreover, Mamet believes that the way people speak influences the way they behave, rather than vice versa. Every comma, every stutter, every emphasis—note that single syllables are often placed in italics—in the play is as Mamet expects it to be performed. The stage directions, however, are so sparse as to be nearly nonexistent. Mamet does not specify how the set looks and almost never specifies what the characters' physical actions may be. Furthermore, at times in Act Two, with characters coming in and out of Williamson's office, Mamet is even ambiguous about who is or is not onstage at certain moments. These physical details are irrelevant to the drama that Mamet is creating, which is all in the talking.
Characters' ability to speak persuasively determines their fate in Mamet's world. Roma is a breathtakingly smooth talker, able to come up with lies and philosophies as quickly as the words can leave his mouth. His continued business success is never in doubt. Levene, on the other hand, is a disastrously poor persuader. We see from his first line—in which he stammers out seven words and pauses before he can even begin his sentence—that he is not well suited to sales. Levene makes desperate pleas throughout the play, yet nearly every argument he makes seems to make things worse for him. Moss and Aaronow, the other two salesmen in the play, fall somewhere in the middle: Moss does not have anything approaching Roma's suavity, but he does have a brute aggression with his words that could conceivably overpower a customer; Aaronow, though meek, at least does not exude desperation the way that Levene does.
Glengarry Glen Ross is a scathing attack on American business practices. The only characters in the play whom we do not witness in some attempt to steal from, cheat, or trick one of the others are Aaronow and Lingk—both extremely meek men who, it is implied, do not have much chance at great success. The sales office of the play serves as a microcosm of capitalist culture: as the top man gets a Cadillac and the bottom man gets fired, every man must not only work for his own success but also hope for—or actively engineer—his coworkers' failure.
The top salesman on the board—at this point, Roma—is also entitled to the best leads. Success, then, is rewarded with further opportunity for success, while failure is punished with the guarantee of further failure. The system is brutal and compassionless. Levene grasps at anything that might help him appear successful, but his guise is unfortunately transparent, which only makes him appear like a greater failure. Like a man flailing in quicksand, Levene's struggle to evade failure at all costs ends up hastening his professional demise. At the play's climax, Levene asks Williamson why Williamson is going to report him to the police, and Williamson responds, "Because I don't like you." This response is borne partly of Levene's having recently insulted Williamson, but it is also because Levene has been emitting an air of failure from the start of the play, and Williamson, a businessman himself, has been trained to fear and hate failure.
Throughout the play, different characters use the word "talk" (or variations of it) to imply idle chatter that is not supported by action. Levene tells Williamson that what he learned in business school is "talk"; Aaronow tries to figure out if Moss is serious about robbing the office or if he is just "talking"; Roma tells Lingk that Mrs. Lingk's insistence on canceling their deal is just something that she "said," not actually something that they have to actually do. In every case, characters use this terminology in an attempt to undermine the "talk" in question. Whenever someone does not want to accept the reality of what it is being said, they make an accusation of "talk." Moss cleverly suggests that he himself is just "talking" about the break-in until he feels that his verbal trap—to force Aaronow to commit the robbery—is set. At that point, Moss reveals that he has actually been "talking" about the break-in. The word is the same but his tone switches the word "talk" itself from meaningless to meaningful.
The salesmen in the play constantly find it to their advantage to suggest that some words are meaningful and others are meaningless. Often, even mid- conversation, they find it to their advantage to suggest that something has switched from meaningful to meaningless or vice versa. A corollary to this strange meaningful-meaningless property of "talk" is the similar case of the word "listen." After Moss tries to convince Aaronow to rob the office, he informs him that he is already an accomplice to the crime; Aaronow asks why and Moss explains, "Because you listened." Listening can go from harmless to criminal in an instant.
Though the salesmen in the play are not, technically, criminals—convincing people to buy overpriced land may be immoral, but not illegal—they all have the mindset of con men. As the capitalist system demands that they compete against each other, they are always on the lookout for any shortcut or trick to get ahead. Moss wants to steal the Glengarry leads but is afraid to actually commit the break-in, so he tries to con Aaronow into doing it; Roma plans to con Levene into giving him half of his commissions; and all of the salesmen, of course, try to con their customers into buying land that they do not want. The most obvious example of a con in the play comes when Roma tries everything he can to ignore Lingk's desire to cancel the deal they have signed. In this instance, the con is not based on subtle manipulation of language, but rather on outright, ridiculous lying.
Though Williamson is not a salesman like the others, he is, like them, also looking for any advantage he can find. He nearly works out a deal in Act One, scene one, to give Glengarry leads to Levene in exchange for twenty percent of Levene's commissions and fifty dollars per lead. Williamson is a "company man" type who is not interested in putting himself at risk. Nonetheless, even he is looking for an "angle" to make more money. Williamson's openness to this deal, which violates company policy, demonstrates that conning and scamming are inherent not just to sales, but to American business in general.
The salesmen in Glengarry Glen Ross repeatedly talk of themselves as "men," and it is clear that this word signifies more to them than merely their gender and age. Manhood, in their parlance, is something that must be earned. Hard work is an important prerequisite to manhood, but steering one's own destiny and living by one's wits are more important. "A man's his job," Levene tells Williamson in Act Two. Because Williamson's job is merely to take orders from Mitch and Murray and pass those orders along to the salesman, it is implied, he is not really a man at all.
This motif is related to the motif of meaningless "talk." To have a big mouth is to be full of "talk." Moss refers to himself as having a big mouth when he is trying to convince Aaronow to rob the office. Moss argues that because he has a big mouth he cannot rob the office, as everyone would immediately figure out that he was the culprit. People expect his "talk" to be meaningless and he must, in this case, maintain that illusion. Levene is another character who is accused of having a big mouth—and when Williamson is about to report Levene to the police, he delights in the opportunity to open his own "big mouth."