The Ramban, in quoting this Ibn Ezra, gives another example from the Megillah: “hipil pur hu hagoral” – “pur” is a Persian word, so the Megillah immediately tells us that it means “goral.”The Ibn Ezra raises this issue to explain a pasuk in our parsha: “beis ha’sohar makom asher asirei hamelech asurim” (39:20) – “beis hasohar” is not a Hebrew word, so the Torah translated that it is “makom asher asirei hamelech asurim.” Ramban disagrees with this example. “Beis hasohar,” says Ramban, simply means prison. There are all kinds of prisons; therefore, the Torah adds that this was specifically a prison “makaom asher asirei hamelech asurim,” where the king’s prisoners were held.
Assuming the Ibn Ezra is correct, the question that begs asking is why Tanach uses foreign words at all. Why use a word like “beis hasohar,” that needs explanation, adding to the length of the pasuk, when an equivalent Hebrew word or just the explanation “makom asher asirei hamelech asurim” could just as easily be used? What assumptions about the vocabulary of the reader are built into the text?
Jumping from pshat to derash, the Tiferes Shlomo suggests that the word “beis hasohar” alludes to the moon, which in Aramaic is called “si’hara.” The waxing and waning of the moon is symbolic of the rise and fall of the Jew in galus. Yosef is not just being thrown into a physical prison – he, and eventually his brothers, will be imprisoned by an exile that will last over 200 years. So we have the Hebrew text of the Torah using what the Ibn Ezra thinks is an Egyptian word being interpreted by the Tiferes Shomo as an allusion to an Aramaic phrase – how’s that for a linguistic roller coaster ride!