Question: Information:  - Siebs ' law is a Proto - Indo - European ( PIE ) phonological rule named after the German linguist Theodor Siebs . According to this law , if an s - mobile is added to a root that starts with a voiced or aspirated stop , that stop is devoiced . Compare : PIE * bHg - > Latin fragor , but * s - bHg - > PIE * spHg - > Sanskrit sphrjati .  - Theodor Siebs (26 August 1862  28 May 1941) was a German linguist most remembered today as the author of "Deutsche Bühnenaussprache" published in 1898. The work was largely responsible for setting the standard pronunciation of the modern German language and is referred to popularly by German speakers as "der Siebs".  - German is a West Germanic language that is mainly spoken in Central Europe. It is the most widely spoken and (co-) official language in Germany, Austria, Switzerland, South Tyrol (Italy), the German-speaking Community of Belgium, and Liechtenstein; it is also an official, but not majority language of Luxembourg. Major languages which are most similar to German include other members of the West Germanic language branch, such as Afrikaans, Dutch, and English. It is the second most widely spoken Germanic language, after English.    What entity does 'siebs' law' has the relation 'instance of' with?
Answer:
language