Senantho's Law is a sound change in the western branch of the Hesperic family. It is named after an ancient Elven grammarian who observed that in Old Albic, the group tha in a suffix (e.g. the agent suffix -thara or the instrument suffix -thal) changes into i when the suffix follows a stop. For example, while 'thinker' is manthara (root man-), 'killer' is matera (root mat-). This is actually an instance of a more general sound change affecting all western Hesperic languages, wherein a stop immediately following another stop is changed into a semivowel. Dental and velar stops become *j (which drops before *w) while labial stops become *w. Another example besides the Old Albic (and cognate West Hesperic) agent and instrument suffixes is the cognacy of the Old Albic Earth goddess name Dime and Valdiska gama 'soil', both from Proto-Hesperic *dgama (cf. PIE *dhǵhom- 'earth'). Geminate stops are unaffected.