Siebs's law is a

Proto-Indo-European Proto-Indo-European (PIE) is the reconstructed common ancestor of the Indo-European language family. Its proposed features have been derived by linguistic reconstruction from documented Indo-European languages. No direct record of Proto-Indo-E ...

(PIE) phonological rule named after the German linguist

Theodor Siebs Theodor Siebs (; 26 August 1862 – 28 May 1941) was a German linguist most remembered today as the author of '' Deutsche Bühnenaussprache'' ("German stage pronunciation"), published in 1898. The work was largely responsible for setting the stan ...

. According to this law, if an

s-mobile In Indo-European studies, the term s-''mobile'' ( ; the word is a Latin declension, Latin neuter adjective) designates the phenomenon where a Proto-Indo-European root, PIE root appears to begin with an ' which is sometimes but not always present. It ...

is added to a root that starts with a voiced or aspirated stop, that stop is allophonically devoiced. Compare: :PIE >

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

'' fragor'', :but > PIE >

Sanskrit Sanskrit (; attributively , ; nominally , , ) is a classical language belonging to the Indo-Aryan branch of the Indo-European languages. It arose in South Asia after its predecessor languages had diffused there from the northwest in the late ...

''sphūrjati''.

Discussion

Siebs proposed this law in the ''Zeitschrift für vergleichende Sprachforschung auf dem Gebiete der indogermanischen Sprachen'', as ''Anlautstudien'' (Berlin, 1904, 37: 277–324).

Oswald Szemerényi __NOTOC__ Oswald John Louis Szemerényi, FBA (; 7 September 1913 in London – 29 December 1996 in Freiburg) was a Hungarian Indo-Europeanist with strong interests in comparative linguistics in general. Biography He was educated in Hungary, at ...

has rejected this rule, explaining that it is untenable and cites the contradiction present in

Avestan Avestan (), or historically Zend, is an umbrella term for two Old Iranian languages: Old Avestan (spoken in the 2nd millennium BCE) and Younger Avestan (spoken in the 1st millennium BCE). They are known only from their conjoined use as the scrip ...

''zdī'' from PIE "be!" as counterproof (Szemerényi 1999: 144). However, the PIE form is more accurately reconstructed as from (so not an s-mobile) and thus Siebs' law appears to demand that the sibilant and aspirated stop are both adjacent and

tautosyllabic Two or more segments are tautosyllabic (with each other) if they occur in the same syllable. For instance, the English word "cat", , is monosyllabic and so its three phonemes , and are tautosyllabic. They can also be described as sharing a 't ...

, something which is known to only occur in word-initial position in Proto-Indo-European anyway.

References

* * Sound laws Proto-Indo-European language {{ie-lang-stub