ENIn his monograph on nominal accentuation in Baltic and Slavic (1963), Illič-Svityč tried to explain why so many PIE neuter o-stems appear to have become masculine in Slavic, an observation which was first made by Hirt (1893). A comparison with accentual data from Baltic, Greek, Sanskrit and Germanic led Illič-Svityč to conclude that PIE barytone neuter o-stems correspond with Slavic masculine o-stems belonging to the barytone class in the case of “long” roots and to the oxytone class in the case of “short” roots (in Stang’s terminology to accent paradigms a and b, respectively). In originally masculine o-stems with a non-acute root, accentual mobility has been generalized (Illič-Svityč’s law). Thus, Slavic masculine o-stems belonging to AP (b) in principle continue old neuters. According to Illič-Svityč, PIE oxytone neuter o-stems remain neuter in Slavic. The majority of the Slavic neuter o-stems belong to the oxytone class (AP b). Mobile neuter o-stems (AP c) contain, as a rule, a historically long root or have a io-suffix. Furthermore, the retraction generally known as Hirt’s law has generated a class of neuter o-stems with fixed root stress (AP a). [...]. [Extract, p. 59]