If so, this could be a part of the reason why we haven't completely deciphered these inscriptions.
Logically, these inscriptions should include mostly Semitic words and Egyptian borrowings. Now, as they are often related to mining, or possibly written by miners, they may include a kind of miners slang, that we would then be unable to interpret, i.e Semitic words with unusual meanings. A major issue is that this "alphabet" is not stabilized. It does not seem to have a limited set of letters with standardized shapes.