But in any case, in the present time Ehret’s work signifies big progress".[8] The sociologist and linguist Gerard Philippson in his review in the Journal of African Languages and Linguistics, also raises questions on some of the semantic connections, and he has doubts about the environments of certain sound changes proposed in the book. He has issues as well with Ehret's use of evidence from the Central Sudanic branch of the Nilo-Saharan family, but he finds his arguments relating to the Eastern Sahelian (Eastern Sudanic) branch convincing and "solid". He avers in conclusion: "Même les chercheurs s'opposant à cette reconstruction disposeront, en tous cas, d'une somme de matériaux, clairement présentés dans l'ensemble, sur lesquels ils pourront s'appuyer pour mettre en cause ou rebâtir l'ensemble proposé.