Sievers's law in Indo-European linguistics accounts for the pronunciation of a consonant cluster with a glide ( or ) before a vowel as it was affected by the phonetics of the preceding syllable. Specifically it refers to the alternation between and , and possibly and as conditioned by the weight of the preceding syllable. For instance, Proto-Indo-European (PIE) became Proto-Germanic *harjaz, Gothic harjis "army", but PIE became Proto-Germanic *hirdijaz, Gothic hairdeis "shepherd". It differs from ablaut in that the alternation has no morphological relevance but is phonologically context-sensitive: PIE followed a heavy syllable (a syllable with a diphthong, a long vowel, or ending in more than one consonant), but would follow a light syllable (a short vowel followed by a single consonant). History Discovery This situation was first noticed by the Germanic philologist Eduard Sievers (1859-1932), and his aim was to account for certain phenomena in the Germanic languages. He originally discussed only in medial position. He also noted, almost as an aside, that something similar seemed to be going on in the earliest Sanskrit texts. Thus in the Rigveda dāivya- "divine" actually had three syllables in scansion (dāiviya-) but satya- "true" was scanned as written. Extension to other branches After Sievers, scholars would find similar alternations in Greek and Latin, and alternation between and , though the evidence is poor for all of these. Through time, evidence was announced regarding similar alternations of syllabicity in the nasal and liquid consonants, though the evidence is extremely poor for these, despite the fact that such alternations would have left permanent, indeed irreversible, traces. For example, the Sanskrit "tool-suffix" -tra- (e.g. pā-tra- "drinking cup, vessel") almost always follows a consonant or long vowel and should have therefore been -tira-; but no such form as **pōtira-, either written as such or scanned thus, is actually attested in the Rigveda or any other Indic text. How a nearly universal suffix **-tira- would have been, or even could have been, uniformly replaced by -tra- is unobvious. Edgerton The most ambitious extension of Sievers's law was proposed by Franklin Edgerton (1885–1963) in a pair of articles in the journal Language ( and ). He argued that not only was the syllabicity of prevocalic consonants by context applicable to all six Indo-European sonorants (), it was applicable in all positions in the word. Thus a form like "sky" would have been pronounced like this only when it