Proto-Riphic

Proto-Riphic is a descendant of Late PIE with a Proto-Germanic and Proto-Balto-Slavic hybrid aesthetic.

Phonology

Proto-Riphic is a satem language, which means that the original PIE palatovelars are fronted to alveolar. It also underwent a sound shift similar to Grimm's law:

• PIE voiceless stops -> voiceless fricatives
• PIE "plain voiced"/glottalic stops -> voiceless stops
• PIE "voiced aspirates" -> voiced stops

Unlike in Proto-Germanic, though, there is no Verner's law in Proto-Nithish.

Proto-Riphic doesn't have a broad/slender contrast in consonants unlike its descendant Nithish.

In addition, Proto-Nithish has lots of loanwords from Uralic languages and Proto-Indo-Iranian, which did not undergo Grimm's law except when Iranian languages have it (i.e. *pr -> fr etc.)

Vowels

Most notably, h2 doesn't color vowels in Nithish languages; this comes from an original sound change *h2 -> /ç/ which later disappears with compensatory lengthening.

eh1 eh2 eh3 oh1 oh2 oh3 -> ē ē ō ā ā ō

The same is true of initial h2; for instance, elceþi from h2el-k-eti "he walks".

Morphology

Proto-Riphic retained all 8 cases of PIE, as well as singular, dual, and plural forms of nouns. Its verbal morphology, though, is much simpler. It's notable for having an evidentiality distinction in verbs from the original PIE sigmatic aorist.