Bartholomae's law (named after the German Indo-Europeanist Christian Bartholomae) is an early Indo-European (PIE) sound law affecting the Indo-Iranian family. It states that in a cluster of two or more obstruents (stops or the sibilant ), any one of which is a voiced aspirated stop anywhere in the sequence, the whole cluster becomes voiced and aspirated. Thus to the PIE root "learn, become aware of" the participle "enlightened" loses the aspiration of the first stop (Grassmann's law) and with the application of Bartholomae's law and regular vowel changes gives Sanskrit buddha "enlightened". Further developments In both the Indic and the Iranian subgroups, further developments partially obscured the operation of the law: Thanks to the falling together of plain voiced and voiced aspirated stops in Iranian, Bartholomae's law appears synchronically as progressive voicing assimilation after roots that originally ended in voiced aspirates, for example Old Avestan "he said" from PIE . This is not true for roots with plain voiced stops, for example Old Avestan "yoked" from , where Bartholomae's law does not apply. In Indic, voiced *z as resulting from Bartholomae's law was devoiced to s, although there is some evidence from the Rigvedic language that a voiced aspirate *z once existed in Indic as well: This is shown by forms like gdha "he swallowed" and dudukṣa- "want to give milk" (see below). Interpretation A written form such as -ddh- (a literal rendition of the devanāgarī representation) presents problems of interpretation. The choice is between a long voiced stop with a specific release feature, aspiration, symbolized in transliteration by -h-, or else a long stop (or stop cluster) with a different phonational state, "murmur", whereby the breathy release is an artifact of the phonational state. The latter interpretation is rather favored by such phenomena as the Rigvedic form gdha "he swallowed," which is morphologically a middle aorist (more exactly "injunctive") to the root ghas- "swallow", as follows: ghs-t-a > *gzdha, whence gdha by the regular loss of a sibilant between stops in Indic. While the idea of voicing affecting the whole cluster with the release feature conventionally called aspiration penetrating all the way to the end of the sequence is not entirely unthinkable, the alternative – the spread of a phonational state (but murmur rather than voice) through the whole sequence – involves one less step and therefore via Occam's razor counts as the better interpretation. Bartholomae's law intersects with