There have been numerous attempts to
decipher the rongorongo script of
Easter Island since its discovery in the late nineteenth century. As with most
undeciphered scripts, many of the proposals have been fanciful. Apart from a portion of one tablet which has been shown to deal with a
lunar calendar, none of the texts are understood, and even the calendar cannot actually be read.
There are three serious obstacles to decipherment: the small number of
remaining texts, comprising only 15,000 legible
glyphs; the lack of context in which to interpret the texts, such as illustrations or parallels to texts which can be read; and the fact that the modern
Rapa Nui language is heavily mixed with
Tahitian and is unlikely to closely reflect the language of the tablets while the few remaining examples of the old language are heavily restricted in genre and may not correspond well to the tablets either.
Since a proposal by Butinov and Knorozov in the 1950s, the majority of
linguists and cultural historians have taken the line that rongorongo was not true writing but
proto-writing, that is, an
mnemonic device, such as the
Dongba symbols of the
Nakhi people, which would in all likelihood make it impossible to decipher. This skepticism is justified not only by the failure of the numerous attempts at decipherment, but by the extreme rarity of independent writing systems around the world.