Комментарии:KW 167, 180, Poppe 17, 18, 43, Цинциус 1984, 76-77. Mergers with phonetically close roots (e. g. *k`ăp`ù 'barrier', *k`ŏ̀p`e 'film, covering', *kobe 'clothing', *k`āp`a 'bladder') were possible - which may explain some vocalic and prosodic irregularities.
