Abstract
This paper explores conceptual and descriptive parallels between the Ancient Greek psi iota lambda alpha-delta alpha sigma epsilon alpha distinction as found in the Peripatetic text De Audibilibus, and the g. ahr-hams distinction in the medieval Arabic writings of Al-.alil (d. c. 786 A. D.) and Sibawayhi (d. c. 796 A. D.). In both cases there is a focus on the absence versus presence of audible breath, and a belief that audible breath is a cause of lack of clarity in speech. There is no historical evidence that the De Audibilibus was available to the Arab grammarians either directly or through Syriac sources, but the striking similarities suggest that ideas expressed in it did make their way into Arabic phonetic thinking. The fact that Sibawayhi applied the distinction to all the sounds of Arabic, and did not introduce a third term equivalent to the later Greek mu epsilon sigma alpha category found in the Techne Grammatike (2nd cent. B. C.) and in Jacob of Edessa's (c. 640-708 A. D.) Syriac grammar based on it, suggests that it was the psi iota lambda alpha-delta alpha sigma epsilon alpha distinction in its original form which influenced his division of Arabic sounds into the mag. hur and mahmus classes.