Eight ancient writing scripts that still can't be read

Decoding antiquity: Eight scripts that still can't be read. «Many ancient scripts have been deciphered [...], but some significant ones have yet to be cracked. These fall into three broad categories: a known script writing an unknown language; an unknown script writing a known language; and an unknown script writing an unknown language. The first two categories are more likely to yield to decipherment; the third - which recalls Donald Rumsfeld's infamous "unknown unknowns" - is a much tougher proposition, though this doesn't keep people from trying. »