Dahl’s Law was formulated by Meinhof in 1904 and named after the missionary Edmund Dahl, who had discovered it in Nyamwezi. The initial formulation stated that when two successive syllables in a stem each begin with a voiceless plosive, the first becomes voiced. In this version, the distinction between plain voiceless stops and aspirates was explicitly treated as irrelevant to the law’s operation.

A later formulation by Meinhof and Van Warmelo in 1932 shifted aspiration to the centre of the explanation. It described a sequence in which two successive syllables begin with aspirates and the first loses its aspiration and becomes voiced. The passage relates this reinterpretation to the second clause of Grassmann’s Law, which concerns the loss of aspiration in the first of two aspirated consonant groups within the same root.

The comparison with Makhuwa remains cautious. Makhuwa’s Katupha’s Law preserves the final aspiration in a stem, while the relevant Swahili processes preserve the first suitable aspiration in the final part of a word. The passage therefore treats the relationship between Dahl’s Law and Makhuwa deaspiration as a problem of comparative phonology rather than as a simple identity between the processes.