Rapa Nui has long fascinated the Western public for its seeming incongruity with the rest of Polynesia, let alone the world in general. The Moai statues permeate modern stereotypes of tropical/tribal culture, while conspiracy theorists desperate for book sales and blog clicks have spewed crap about their "enigmatic" uses, creation, and/or origin. Some interpretations are better than others.
Unfortunately this interest flowed over into academia, generating far more speculative scholarship than our limited sources merit, particularly in relation to Rongorongo (RR). Decipherment is a morass of self-published aspirations, unpublished analyses, and wishful thinking. Legitimate inquiries still focus on quantitative linguistics, general structural comparisons with ethnographic texts, and developing a consistent inventory of signs. But that's for another time...
What we want is the origin, and unfortunately, from a purely positivist perspective, there's no good consensus. Researchers effectively treat it as an independent script, i.e. they're not looking for connections with outside languages (anymore). There's no verifiable evidence to say that it originated completely independently, but the dispersion and contact theories are lacking. Let's discuss those:
Pre-colonial dispersion: Back in 1932, a Hungarian engineer proposed a popular theory that RR was connected to the Indus Valley script, and I still see people promoting this idea. Some have argued that RR is the result of contact with South America. Such contact is all but certain, yet it doesn't tell us much. Andean civilizations on the western coast had no writing either. Robert Langdon insisted that is was inspired by the descendants of a shipwrecked Spanish merchant vessel who supposedly helped populate New Zealand and Polynesia, a scenario which itself is not generally accepted. Importantly, as I mentioned in that earlier post, there's no "missing link" that appears as an intermediate between RR and another script. Like so many other things on Rapa Nui, it's an isolate.
Inspiration from Contact: In the 90s, Steven Fischer advocated that a group of Spaniards who sailed from Peru to Easter Island inadvertently inspired the RR script by forcing the natives to sign a treaty, thus sparking the idea of writing. With only occasional outside contact, the script would have developed "independently" after the Spanish impetus. Langdon obviously took issue with this idea, and their debate on the issue is engaging, if not for its own content at least for the uncertainty with which other scholars viewed both parties' claims. Neither has particularly compelling work, but at least they were trying. The treaty in question did exist, but the original has since been lost and is preserved only through illustrations. Fischer posits that later reproductions modified the original to fit known images of RR. Langdon reasonably argues the authenticity, and points out that the locals cannot be expected to have written neatly with a quill pen when used to inscribing on wood. This also correlates with the recorded statement that they "signed in their own letters." We also must take into account this theory's timing: it would leave just over 100 years for the script to be conceived, used, and forgotten. But... we have yet to reliably date any RR tablets to before contact. The best pre-contact evidence is this debated deed.
Again, these theories have so little going for them, but it's not like we have positive evidence to say otherwise. They're just bad theories. We treat RR as its own creation in analysis, which, for me, is what counts. If you look into the more recent investigation from Daveltshin and Melka, you see a lot of "provisional" and "tentative" results. Compared to other scripts, we have such a paucity of colonial period sources and individual texts that understanding RR is a monumental task. Add in that there's no bilingual texts (e.g. Rosetta Stones), and you'll find that good answers are still a bit away.
Daveltshin, A.. (2012). "Numerals and Phonetic Complements in the "Kohau Rongorongo" Script of Easter Island." The Journal of the Polynesian Society, 121(3), 243–274
Harris, M., & Melka, T. S. (2011). The Rongorongo Script: On a Listed Sequence in the Recto of Tablet 'Mamari'. Journal Of Quantitative Linguistics, 18(2), 122-173.
Langdon, R., & Fischer, S. R.. (1996). "Easter Island's 'deed Of Cession' Of 1770 And The Origin Of Its Rongorongo Script." The Journal of the Polynesian Society, 105(1), 109–124.
Makihara, M.. (2001). Review of Rongorongo: The Easter Island Script. History, Traditions, Text. Anthropological Linguistics, 43(1), 111–115.
Orliac, C.. (2005). The "Rongorongo" Tablets from Easter Island: Botanical Identification and 14C Dating. Archaeology in Oceania, 40(3), 115–119.
