Bartholomae's Law

Bartholomae's Law describes a process of aspiration transfer in Indo-Iranian that operated when a voiced aspirated stop was immediately followed by a voiceless stop or other obstruent. In this environment, the aspiration moved from the first consonant to the second, and both consonants became voiced. The most frequently cited example involves the PIE root *bʰewdʰ- 'to be aware.' In the past participle, the suffix *-to- is added to the root, creating the cluster *dʰ-t. By Bartholomae's Law, this becomes *d-dh, yielding Sanskrit buddha- 'awakened, enlightened' — famously the epithet of Siddhartha Gautama. The law can be formalized as follows: when an aspirated voiced stop (such as *dʰ, *bʰ, or *gʰ) precedes a voiceless stop (such as *t), the aspiration shifts to the following consonant, and the first consonant loses its aspiration but remains voiced. The result is a sequence of plain voiced stop plus voiced aspirated stop. Bartholomae's Law interacts importantly with Grassmann's Law in Sanskrit. Since Bartholomae's Law creates new aspirated consonants, these can then trigger Grassmann's dissimilation. In the case of *bʰewdʰ-to-, Bartholomae's Law first gives *bʰud-dha-, then Grassmann's Law dissimilates the first aspirate, yielding buddha-. The law is well established for Indo-Iranian and may have operated in PIE itself, though this remains debated. Its effects are clearly visible in Sanskrit verbal morphology, particularly in the formation of past participles and certain noun stems from roots ending in aspirated stops.