A pseudotranslation is a text written as if it had been translated from a foreign language. J. R. R. Tolkien made use of pseudotranslation in The Lord of the Rings for two reasons: to help resolve the linguistic puzzle he had accidentally created by using real-world languages within his legendarium, and to lend realism by supporting a found manuscript conceit to frame his story.
Effectively, he pretends to be an editor and translator who has received an ancient manuscript, the Red Book of Westmarch, written in Westron, the Common Speech of Middle-earth, annotated and edited by many hands, which he decides to translate into English. The manuscript contains names and words from other languages, some of them related to Westron; he translates those into languages related to English, namely Old English and Old Norse. Tolkien wrote in the text of The Two Towers that Orthanc had two meanings, one in Sindarin and the other, "Cunning Mind", in Rohirric. The latter meaning is the actual sense of the Old English word, making the multiple homonymy and synonymy implausible.
Aspects of the pseudotranslation make actual translation of The Lord of the Rings into other languages a challenge. A specific difficulty is the elaborate relationship between some of the real and invented languages used in the book. Westron is supposedly translated as modern English; this stands in relation to Rohirric, an archaic language, which is represented by Old English, and the language of Dale, translated as Old Norse. The three real languages are related. Thomas Honegger gives possible solutions that begin to handle this in French and German, but suggests that the small amount of Old English is probably best left untranslated.