I am aware that obligatory expletives did not exist in early ON and perhaps also not in early OHG, but my knowledge of the specifics is hazy. In OE at least, I believe expletives in conjunction with weather-verbs dates back as far as we have attestations of weather verbs.
I lean to the hypothesis that there is no evidence for them, or that if there is, it is confined to specific semantic types of verb. I was having a discussion with someone about whether it makes sense to posit an etymological or null (which imo are very different things) dummy subject in oblique subject constructions; to me, this seems to add unnecessary assumptions given both typological and IE-internal evidence. Any further reading relevant to this corollary is welcome.
To give a few data points: Latin and Classical Greek don't have dummy subjects and they even drop subject pronouns for non-dummy subjects. Some modern Romance languages are still pro-drop languages (pro-drop is a technical term to watch here) while others like French require obligatory subject pronouns now. Baltic, Slavic, and Indo-Aryan languages are pro-drop, too.
These data already suggest that Proto-Indogermanic was pro-drop although I cannot quote a published result on this. I have no idea on Proto-Germanic because I don't know Gothic well enough.
Answered by jk - Reinstate Monica on November 20, 2020
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