The play was originally written in English, but the real people in the exchange may have had the 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.