Yes, you need the source material, but the things you can infer from it alone are less numerous. With no living speakers, you can map writing to meanings but n

Yes, you need the source material, but the things you can infer from it alone are less numerous. With no living speakers, you can map writing to meanings but not to phonetics, which are one of the main sources to trace language lines. Is the city of "Ass'n" in one language the city of "Hassim" in another? Are two sources talking about the same person or are the names different? Is this text poetry? Is this word here for the rhyme or does it have a specific meaning?