I've recently gotten back from travelling in Mali and Senegal. At the conference I was attending in Bamako, I met several delegates from the N'Ko movement. N'Ko is an old Manding term, meaning "I say" in each of the mutually comprehensible Manding languages (principally Bambara, Maninka, Mandinka, and Dyula) and hence traditionally used as a general term to cover Manding. In 1949, a Guinean Maninka-speaking shaykh, Solomana Kanté, stung by a Lebanese claiming in the newspaper that African languages could not be written and were thus worthless, decided to start writing his language. He experimented with Arabic and Latin scripts, but found them inadequate to Maninka's tone and vowel systems; so he devised a new alphabet, N'Ko. He went on to write nearly two hundred books in the new script, including a translation of the Qur'an, textbooks of physics and history, descriptions of traditional medicine, and books of poetry; his disciples carried on the task after his death, and the script has spread surprisingly widely, mainly in Guinea and Cote d'Ivoire.
After the conference, I wandered around Bamako a bit, and randomly ran across a market stall with N'Ko writing all over it. Naturally, I went over and asked about it; it turned out to be a traditional medicine shop. All the remedies were labelled in N'Ko, and the shop's accounts (I happened to notice) were kept in N'Ko; apparently, the stallholder used Solomana Kante's works on traditional Manding medicine... In the next stall, where they were setting up a bookstore, was an N'Ko teacher. I ended up having quite a long discussion with him; the topic was interesting enough that I didn't even notice that he had 12 fingers until an hour later, although that did make the meeting more memorable.
He showed me some books in N'Ko (textbooks of maths, physics, and geography, a grammar, a philosophical work, a newspaper, and the Qur'an translation) and spoke eloquently about what a difference it made to have access to knowledge in your own language for once. He had studied algebra and geometry through highschool, in French, without understanding them; yet when he read about them in his own language, the concepts became easy. Studying in French, he argued, you became alienated from yourself and your culture as the price for your knowledge; studying in N'Ko, your knowledge fit naturally into your own identity. Despite the funding of literacy organizations, the inadequate, atonal Latin orthography for Bambara was still virtually unused, while N'Ko (he claimed implausibly) was being studied by most of Bamako. He also explained something I hadn't realized: the N'Ko movement uses a common standardized language, a literary Manding "purified" of Arabic and French borrowings, utilising the most conservative dialects, and full of agglutinatively coined neologisms for modern technical terms, thus creating a dialect that they felt could compete with French in all usages rather than being restricted to low registers and simple topics.
I was impressed. It looks to me like N'Ko enjoys one massive advantage over Latin: not the tones, nor even the books (though they help!), but the evangelical dedication it inspires in its devotees, without which a literacy program in an unwritten language is unlikely to overcome the obstacles it faces.