More than seven million people in southern Ethiopia speak a Highland East Cushitic language: Burji, Hadiyya, Kambaata, Sidaama or Gedeo. newly graduated Dr. Ahmed Sosal investigated how these languages are related.
Eastern Cushitic comprises more than thirty languages, which are thought to have originated from a single common ancestral language. However, evidence for this theory was lacking. It fell to Sosal to investigate the lineage of five of these languages, that belong to the Highland East Cushitic branch within East Cushitic.
In search of the family tree
For his research, Sosal used a comparative database that precisely records how words sound. 'As time passes, sounds often become weaker,' he explains. 'Between vowels, an original "b" weakens to a "w" over time and can eventually disappear; the same happens with "k" becoming "h" and then vanishing. Sometimes the same word is pronounced in three different ways across three different languages. Then you know that one language has retained the old pronunciation, whilst in another language it is fading or has even disappeared.'
By mapping such changes, Sosal was able to reconstruct a family tree of the five languages, which confirms an older hypothesis. 'Burji split off earlier, after which the other four went on to form a separate group. However, no one had yet attempted to reconstruct the intermediate ancestor language, even though it does exist.'
Between the proto-language of Eastern Kushitic and the five languages studied by Sosal lies Highland Eastern Kushitic. Sosal: 'The reconstruction of this language is one of the most significant contributions of this research.'
Language contact and heredity
Another important finding of his research is the influence of language contact. 'This has long been seen as something that occurs only occasionally,' says Sosal. 'I demonstrate that, in fact, it happens constantly. That constant contact disrupts the regularity of sound changes, making it important to distinguish between sound changes caused by contact and the regular changes caused by inheritance.'
Burji in particular has been strongly influenced by a language such as Oromo, although the two other southern languages, Gedeo and Sidaama, also show clear traces of this. Sosal: 'That is geographically relevant, because it shows what contacts existed at the time.' Moreover, it refutes another hypothesis. 'Initially, I thought Burji was the most conservative language, as it most closely resembled the other East Cushitic languages. It seemed logical that the proto-language had been best preserved in it. Thanks to my research, we now know that those conservative elements have not been preserved in Burji, but have re-emerged in it through contact with other languages.'
