1 The following symbols will be used (cf. Franklin Edgerton, Lg. 19.83–124) : A = any short vowel ; Ā = any long vowel ; T = any consonant ; KT = any consonant cluster ; R = any semivowel in nonsyllabic (consonantal) function; ṚR = semivowel in syllabic (vocalic) function; Ṛ↠ = any semivowel in syllabic-plus-nonsyllabic function. The last of these is called the Sievers'-law variant. Z denotes utterance-initial or final position (Edgerton uses a slant-line, which has come to indicate phonemic transcription.)

A ‘heavy syllable’ has the structure -AKT- or ĀT-, a ‘light syllable’ has the structure -AT-.

2 The conditions for the double treatment of the vocalic allophones are not germane to the present discussion.

3 Jerzy Kuryłowicz, L'apophonie en indo-européen 219 (Wrocław, 1956).

4 Grammaire comparée des langues slaves 169 (Paris, 1950).

5 A hypothesis about the way in which Sievers'-law variants became phonemic is the following (cf. Kuryłowicz, L'apophonie 171). At an early stage of Balto-Slavic there were contrasting phonemic sequences of the type */ATRHA/ (phonetic *[ATṚHA]) and /ATRA/, where -R- and -Ṛ- are members of the same phonene and H represents a laryngeal. When the laryngeals were lost, the original vocalic and consonantal allophones came into contrast, i.e. became separate phonemes.

6 Kuryłowicz suggests the possibility of the action of Sievers' law, but does not state it explicitly with regard to the Baltic and Slavic verbs. In L'apophonie 171 fn. 12 he says, TaR à la place de TR au sud, tout comme TuR (germ.) ou TiR (balto-slave) à la place de TR dans les langues septentrionales, peuvent aussi provenir de l'action de la loi de Sievers.‘ He refers here only to the effect of a preceding long vowel, but makes no comment on the Sievers‘-law reflex of semivowels in utterance-initial position.

7 I omit the problem of the Lith. /o/ for expected /uo/ < IE /eH₃/ in žinóti.