plain voiced plosives the vowels were lengthened, which is not the case with the aspirated voiced ones (Winter's law). The Proto-Baltic was a satem language, PIE *ḱ turned into *š, PIE *ǵ and PIE *ǵʰ turned into *ž. The semivowels of PIE *ṛ, *ḷ, *ṃ, *ṇ, which were used as vowels or to form a syllable, turned into mixed diphthongs *ir, *il, *im, *in (in rarer cases—*ur, *ul, *um, *un) in Proto-Baltic. These diphthongs alternated with *er (*ēr), *el (*ēl), *em (*ēm), *en (*ēn) and *ar (*ōr), *al (*ōl), *am (*ōm), *an (*ōn). One of the unique properties of Baltic languages is the disappearance of the semivowel *i̯ between a consonant and a front vowel (e. g., *žemi̯ē > *žemē 'earth'). Another noteworthy trait of Proto-Baltic is the retained intact *m existing before front dental consonants *t, *d, *s (e. g., *šimtan 'hundred', *kimdai 'gloves', *tamsā 'darkness'), which in other Indo-European languages turned into n. However, unlike in Italic or Indo-Iranian languages, in Proto-Baltic *m and *ṃ would become *n at the very end of a word. Stress and pitch accent In the Proto-Baltic language, the stress could be placed on any syllable, the stress was free, unfixed. According to the movement of stress, three possible variants of accent system are reconstructed: 1) a system with baritone accentuation (stress on the stem) and oxytonic accentuation (stress on the endings), 2) a system with baritone accentuation and mobile accentuation (stress moves from endings to the stem), 3) a system with the baritone, mobile and oxytonic accentuations. There were two pitch accents, an acute (´) and a circumflex (˜), which were pronounced with pure and mixed diphthongs and long vowels. Pitch accents could be pronounced both in the stems and in the endings. The acute pitch had a rising intonation, while the circumflex pitch had a falling intonation. Some scientists (Zigmas Zinkevičius, Vytautas Kardelis, etc.) believe that pitch accents were pronounced both in stressed and unstressed syllables, for example *'rãnkā́ 'hand' (stress placed on the first syllable, although both syllables had different pitch accents). Morphology Nouns The noun of Proto-Baltic possessed very archaic traits—the endings were not being shortened and were close to the endings of PIE. It had three grammatical categories: gender (masculine, feminine and neuter), number (singular, dual and plural) and seven cases: nominative, genitive, dative, accusative, instrumental, locative and vocative with three different dual case forms. In comparison to