Though the dialogue does not contradict logic, it cannot be called realistic in the strictest sense. One character's line might fade into the next, as though the second person knew exactly what he was going to say; sometimes a character will slip into a memory and partially relive a former or younger self in a monologue; and over the course of the show, there is a definite ambiguity as to whether they are speaking to one another or to the audience.
The play was originally written in English, but the real people in the exchange may have had this conversation in Danish or German. But even with translation in mind, Frayn defends that the words in the script are those that the characters would actually say. In his post-script, he writes, "If this needs any justification, I can only appeal to Heisenberg himself." Understandably, Frayn needs to present the characters in an interesting and dramatic light, as well as depicting a setting that no living person has visited, so the accuracy of such dialogue is subject to dwindle by degrees.
Plain language and scientific language both operate in this play. There are several instances when the two physicists start speaking too scientifically for many people to understand, and one of them will remark that they must revert to plain language, to explain it in a way that Margrethe will understand. Even for this effort though, criticism arose about the complexity of the play and the difficulty for viewers to comprehend. A writer for The Commonweal commented on the Broadway premiere, saying that "the play's relentless cerebral forays can... be frustrating."