Winter's Law
Branch: Balto-SlavicDiscovered by Werner Winter (1978)
V → Vː / _ C[+voiced, -aspirated] (Balto-Slavic)A Balto-Slavic sound change in which vowels were lengthened before PIE plain voiced stops (*b, *d, *g) but not before PIE voiced aspirated stops (*bʰ, *dʰ, *gʰ). This compensatory lengthening helps distinguish the two PIE stop series in Balto-Slavic.
Sound Correspondences
| PIE Form | Reflex | Environment | Examples |
|---|---|---|---|
V + *d | BSl Vː + d | Before plain voiced stop | *séh₁d- → Lith sėkla (long vowel before *d) |
V + *dʰ | BSl V + d (short) | Before voiced aspirated stop | *h₁edʰ- → Lith ėsti (short vowel before *dʰ) |
V + *b | BSl Vː + b | Before plain voiced stop | Lengthening before *b in Balto-Slavic |
V + *g | BSl Vː + g | Before plain voiced stop | Lengthening before *g in Balto-Slavic |
Discussion
Winter's Law, formulated by Werner Winter in 1978, describes a compensatory vowel lengthening in Balto-Slavic that provides crucial evidence for the PIE stop system. According to this law, vowels were lengthened before PIE plain voiced stops (*b, *d, *g) but remained short before the corresponding voiced aspirated stops (*bʰ, *dʰ, *gʰ).
Since the Balto-Slavic languages merged the PIE voiced and voiced aspirated stop series (both becoming plain voiced stops), Winter's Law is one of the few diagnostics available for distinguishing which PIE series a given Balto-Slavic voiced stop continues. A long vowel before the stop suggests PIE *b, *d, or *g, while a short vowel suggests *bʰ, *dʰ, or *gʰ.
The classic example involves the word for 'seed': PIE *séh₁d- (with a plain *d) appears in Lithuanian as sėkla with a long vowel, consistent with Winter's Law. Compare this with PIE *h₁edʰ- 'to eat' (with aspirated *dʰ), which gives Lithuanian ėsti with a short vowel.
Winter's Law remains somewhat controversial. Some scholars have questioned its regularity, pointing to apparent counterexamples. Others have proposed modifications, such as restricting the law to certain prosodic or syllabic contexts. Frederik Kortlandt has been a major proponent, arguing that the law reflects a period of glottalization in Balto-Slavic (connecting it to the glottalic theory of PIE stops), while others maintain the traditional interpretation.
Despite ongoing debate, Winter's Law has proven to be a valuable tool in PIE reconstruction, providing independent evidence for the distinction between the plain voiced and voiced aspirated stop series — a distinction that is otherwise difficult to establish from Balto-Slavic data alone.