WRITING is one of the greatest inventions in human history. Perhaps the greatest, since it made history possible. Without writing, there could be no accumulation of knowledge, no historical record, no science - and of course no books, newspapers or internet.
The first true writing we know of is Sumerian cuneiform - consisting mainly of wedge-shaped impressions on clay tablets - which was used more than 5000 years ago in Mesopotamia. Soon afterwards writing appeared in Egypt, and much later in Europe, China and Central America. Civilisations have invented hundreds of different writing systems. Some, such as the one you are reading now, have remained in use, but most have fallen into disuse.
These dead scripts tantalise us. We can see that they are writing, but what do they say?
That is the great challenge of decipherment: to reach deep into the past and hear the voices of the dead. When the Egyptian hieroglyphs were deciphered in 1823, they extended the span of recorded history by around 2000 years and allowed us to read the words of Ramses the Great. The decipherment of the Mayan glyphs revealed that the New World had a sophisticated, literate civilisation at the time of the Roman empire.
So how do you decipher an unknown script? There are two minimum requirements. First, there has to be enough material to work with. Secondly, there must be some link to a known language. It helps enormously if there is a bilingual inscription or identifiable proper names - the Rosetta Stone (see image), for example, is written in both ancient Egyptian and ancient Greek, and also contains the name of the Ptolemy dynasty. If there is no clear link, an attempt must be made to relate the concealed language to a known one.
Many ancient scripts have been deciphered (see "The great decipherments" and The ancient scripts), 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.
Most of the undeciphered scripts featured here have been partially deciphered, and well-known researchers have claimed that they have deciphered some much more fully. Further progress is possible for most of them, especially if new inscriptions are discovered, which fortunately happens fairly often.
The article then goes on to discuss Etruscan, Meroitic Hieroglyphs (from the Kushite pharaohs), Ancient American Languages (Olmec, Zapotec, and Isthmian), Linear A, Rongo-Rongo (from Easter Island), the Indus Script, Proto-Elamite, and (perhaps) the Phaistos Disc.