The second great linguistic work carried out by Koelle during his five years in Sierra Leone was the
Polyglotta Africana. The idea of this was to use the fact that Sierra Leone was a melting pot of ex-slaves from all over Africa to compile a list of 280 basic words (a sort of early
Swadesh list) in some 160 languages and dialects. These were then grouped as far as possible in families. Most of the informants who contributed to this work came from West Africa, but there were also others from as far away as
Mozambique. One area that was lacking was the
Swahili coast of
Kenya and
Tanzania, since it seems that slaves from this region were generally taken northwards to
Zanzibar and Arabia rather than southward towards America and Brazil. The pronunciations of all the words were carefully noted using an alphabet similar, though not identical, to that devised by
Karl Richard Lepsius, which was not yet available at that time. The name of the book was imitated from a well-known work called
Asia Polyglotta (1823) by the German scholar
Julius Klaproth. In the introduction Koelle tells us that he wanted a selection of words that would be simple enough for each informant to be interviewed on a single day, and for this reason he omitted pronouns, which would have taken much longer to elicit. He adds that a few years earlier during a long vacation he had made a similar such list, of just 71 languages, and that in making the present list he had learnt from that experience. Included with a book is a map of Africa showing the approximate location, as far as it could be ascertained, of each language, prepared by the cartographer
August Heinrich Petermann. The value of the list is not merely linguistic, since the work not only includes the words themselves, arranged with all the languages spread out on two facing pages for each group of three English words, but Koelle also added a short biography of each informant, with geographical information about their place of origin, and an indication of how many other people they knew in Sierra Leone who spoke the same language. This information, combined with a census of Sierra Leone conducted in 1848, has proved invaluable to historians researching the African slave trade in the 19th century. Of the 210 informants, there were 179 ex-slaves (two of them women), while the rest were mostly traders or sailors. An analysis of the data shows that typically Koelle's informants were middle-aged or elderly men who had been living in Freetown for ten years or more. Three-quarters of the ex-slaves had left their homeland more than ten years earlier, and half of them more than 20 years before; and three-quarters of the informants were over 40 years old. Another interesting facet of the book is the manner in which the informants had been made slaves. Some had been captured in war, some kidnapped, some sold by a relative, others condemned for a debt or sentenced for a crime. ==Grammar of the Kanuri language==