The Hebrew that is translated as “firmament,” “expanse,” or “dome” in English is translated in Roviana as galegalearane: “the open space between the earth and the sky” and in Moru as “empty space.”
In Idoma it is translated as okpanco — “the top of the sky.” “According to tradition, when the world began, the okpanco was low. A woman was pounding yams and her pestle kept hitting okpanco and it started going higher and higher.”
In Naskapi it is translated as “sky skin” — “like a caribou skin.”
(Sources: Roviana: Carl Gross; Moru: Jan Sterk; Idoma: Rob Koops; Naskapi: Doug Lockhart in Word Alive 2013)
In Lingala it is translated as “surface.” Sigurd F. Westberg (in The Bible Translator 1956, p. 117ff.) explains: “The ‘firmament’ in Genesis 1 gave us another problem. Its meaning in English is certainly not immediately obvious. The dictionary tells us that the Hebrew means something close to our English word ’expanse.’ It seems, however, that the Hebrew idea may not always have been as abstract as that, for Isaiah says that the Lord ‘stretcheth out the heavens as a curtain, and spreadeth them out as a tent to dwell in.’ But the Greek word used in the Septuagint gives the idea of a firm and solid structure, and this is the idea that is carried out in our English word ‘firmament.’ Modern translations into English, Swedish, Norwegian and French take one or the other of these two leads. It is the predicament of the translator that he dare not hesitate too long between ideas. (…) In this case we tried to arrive at ’expanse’ by the use of a word meaning ’width,’ but we found that it is not really understandable except as it is associated with the noun of which it indicates the width. It cannot be used alone. The word we finally used means ‘surface,’ but it also has the idea of something stretched out or smoothed out. It is more concrete than we should like, but it does not require identity with a concrete object as does the word for width’.’
In Newari it is translated as “upper part of water” (Gen. 1.6 is translated “height between two portions of water.”) (Source: Newari Back Translation)