The article discusses the treatment of *-oi in the Slavic language, which is characterized by multiple special phonological treatments of word-final segments, each standing in contrast to a generally valid rule. Topics discussed include claims for the synchronic distribution of the two outcomes of *åi#, the meaning of the older explanation on the rise of the Balto-Slavic intonations and the Jagic's hypothesis on the dual treatment of the final acute syllable.