Sound correspondences of Eastern Baltic languages and lects
Phonology of Common Baltic
The story must begin with the Common-Baltic (later CB) phonological inventory from which each of the languages will diverge very similarly and yet with differences.
| Labials | Coronals | Dorsals | |
|---|---|---|---|
| Plosives | *p *b | *t *d | *k *g |
| Sibilants | *s (*z) *š *ž | ||
| Sonorants | *m *u̯ | *n *r *l | *i̯ |
| ī̆ | ū̆ | |||
| ē̆ | ō | |||
| ā̆ | ||||
As seen in the Table 2 CB vowels, all vowels except for the *ō had long and short counterparts, *ō, however, was only long as the short ŏ (PIE *o, *h₃o, *h₃e) merged with the short *ă.
Due to the accentuation/prosody and the upcoming sound changes it’s worth mentioning that every member of the sonorants class could form a phonetic tautosyllabic diphthong:
| *ĭ | *ŭ | *ĕ | *ă | |
| *i̯ | *ĕi̯ | *ăi̯ | ||
| *u̯ | *ĕu̯ | *ău̯ | ||
| *n | *ĭn | *ŭn | *ĕn | *ăn |
| *m | *ĭm | *ŭm | *ĕm | *ăm |
| *l | *ĭl | *ŭl | *ĕl | *ăl |
| *r | *ĭr | *ŭr | *ĕr | *ăr |
| *ī | *ū | *ē | *ā | *ō | |
| *i̯ | *ēi̯ | *āi̯ | *ōi̯ | ||
| *u̯ | *ēu̯ | *āu̯ | *ōu̯ | ||
| *n | *īn | *ūn | *ēn | *ān | *ōn |
| *m | *īm | *ūm | *ēm | *ām | *ōm |
| *l | *īl | *ūl | *ēl | *āl | *ōl |
| *r | *īr | *ūr | *ēr | *ār | *ōr |
The existence of diphthongs where the first member is long is basically limited to happen in the inflectional endings, although, the word *dōu̯bē (a pit) is believed to have had it in the root. In the table CB diphthongs diphthongs in the non-green background are dubious. The cases of *ii̯ > *ī, *uu̯ > *ū are uncertain as it might have happened in in Pre-Common-Baltic times and later it probably got extended even more.
Developments of Common Eastern Baltic phonology
The most important and probably the sole phonological difference setting Western and Easter Balts (later EB) apart is the the diphthongs *ei, (likely less common *ai, *ēi, *āi) becoming a separate foneme > *ẹ̄. Yet the frequency of this change differs among languages - Latvian and Latgalian have it a bit more frequently while in Lithuanian and Samogitian it's slightly rarer - compare Lithuanian deivė and Latvian dieve/dieviete (goddess in both languages).
| *ī | *ū |
| *ẹ̄< *ei | *ō |
| *ē< *ē | *ā |
| *i | *u |
| *e | *a |
Diphthongs and sonorant diphthongs become more simplex - the difference between long and short diphthongs got neutralised: *ēi̯ > *ei̯, *āi̯ > *ai̯, etc, as well as *ōu̯ > *ō. Kortlandt reconstructs *ōi̯ > *ai̯ in open flectional endings and *ō > *ā in unstressed (stem?) syllables.
Meanwhile the consonant system remained the same.
Developments of each Eastern Baltic language
To be continued