Hysterokinetic

The PIE word for ‘father’ was hysterokinetic: nominative singular *ph₂-tér-s, genitive *ph₂-tr-és.

Hysterokinetic ('later-mobile'): the accent moves between the stem and the ending. Ablauting endings were in full grade. Certain kinship terms, and most r- and n-stems (179-87), went like this: nom. **p-H̥₂-ter-s (*pH̥₂tḗr) 'father', gen. *p-H̥₂tr-ós, acc. *p-H̥₂tér-m̥, and so on. The type is much better preserved than the other three, which means that our understanding of the distribution of ablaut grades of both stem and ending is the most complete for this type

G Ζεύς, L Iuppiter, Iovis reflect a PIE paradigm built to an ablauting stem *dyew-, *diw-/*dyu- 'blue sky, day' (zero grade *diw- before vowel, *dyu- before consonant). [...] In the root noun, the ablaut scheme was hysterokinetic: full grade in the nom. and acc. of all numbers, and the loc.sg.; zero grade elsewhere.

The other three polysyllabic types exhibited alternating accent: on the leftmost syllable of the stem in the direct cases and on the endings in the oblique cases ('amphikinetic' accent); on the rightmost syllable of the stem in the direct cases and on the endings in the oblique cases ('hysterokinetic' accent); or on the penultimate syllable of the stem in the direct cases and on the rightmost syllable of the stem in the oblique cases ('proterokinetic' accent). Note that in every one of these patterns the accent was to the left in the direct cases and to the right in the oblique cases.

In hysterokinetic nouns, the suffix is accented in the strong cases, the ending in the weak. The noun for 'father' is an example: nomin. sing. *ph₂-tér-s (the probable original form, later *ph₂-tēr; recall §6.6), accus. sing. *ph₂-tér-m̥, genit. sing. *ph₂e-tr-és, reflected almost exactly in Gk. patḗr patéra patrós.