Yes, that would be deciphering in a sense... in a sense to use "decipher" for "translate" is already an analogy, since "cipher" means to calculate or to write i

Yes, that would be deciphering in a sense... in a sense to use "decipher" for "translate" is already an analogy, since "cipher" means to calculate or to write in a code, and "decipher" means to reverse the code... which is not exactly what's happening here if the language was not enciphered but merely obscure, but it's a natural enough extension of the meaning of the word.