Borrowing disrupts historical processes of change and makes it difficult to reconstruct the genealogy of languages.
[4] Most scholars reject the Southwest Semitic subgrouping because it is not supported by any innovations and because shared features with South Arabian and Ethiopic were only due to areal diffusion.
[8] Edward Ullendorff even thinks it is impossible to establish any genetic hierarchy between Semitic languages.
[4] For instance, in Garbini's view, the Syrian Desert was the core area of the Semitic languages where innovations came from.
That is why Garbini considers that Arabic does not belong exclusively to either the Northwest Semitic languages (Aramaic, Phoenician, Hebrew, etc.)