German questions

[WeepingElf]

Probably a long shot, but does anyone know how did Proto-Germanic *ajjō 'eggs' become Proto-West Germanic *aijiʀu 'id.'? Going off wiktionary here:
https://en.wiktionary.org/wiki/Reconstr ... manic/ajją
https://en.wiktionary.org/wiki/Reconstr ... rmanic/aij

I guess I'm ultimately curious why German has Eier instead of *Eie or sth, given that the PIE neuter plural ending is *-eh₂.

I cannot tell you how exactly that happened, but at some point, German innovated a neuter plural ending -er which triggers umlaut. There are plenty such neuter plurals, such as Häuser 'houses', Bücher 'books' and Löcher 'holes'.

[Linguoboy]

I cannot tell you how exactly that happened, but at some point, German innovated a neuter plural ending -er which triggers umlaut. There are plenty such neuter plurals, such as Häuser 'houses', Bücher 'books' and Löcher 'holes'.

I thought it was pretty well established that this alternation was generalised from the relatively small class of Proto-Germanic z-stem nouns which continue the PIE athematic acrostatic neuter declension with *-os/-es alternation.

E.g. PIE *h₁l̥h₁onbʰos/*h₁l̥h₁onbʰes- > PGmc *lambaz/*lambiz- > PWGmc *lamb/*lambiʀ- > OHG lamb/lembir-, Mod.Ger. Lamm/Lämmer.

The generalising tendency is already on display in the Proto-West-Germanic period and only gains steam in OHG and MHG due to the large number of neuter nouns inherited without distinctive N/A plural endings. (This contrasts with English where the -s ending was generalised instead and Swedish which was content to leave the vast majority of these nouns without distinctive plurals. Cf. Eng. lamb/lambs, Sw. lamm/lamm.)

[Zju]

And here was I thinking that German and English plural markers -er and -s were cognates, what with rhotacism and such.

[WeepingElf]

Ah, I understand now.