I learned yesterday that (at least in the past sense) Persian third-person plural subjects take singular verbs if the subject refers to things, but plural verbs if the subject refers to people. (Although a lot of people, including the Teach Yourslef Persian book I was looking at, will say there is no gender in Persian, there are distinct third-person pronouns for people (same for male and female) and things.). (I don't know if the rule applies in other tenses.)
Similarly in Greek, neuter plural subjects take singular verbs.
I wondered if it was a rule in proto-Indo-European, and it turns out it is.
In Arabic, plurals of nouns that refer to non-rational beings (i.e. things and animals but not humans, angels, djinn, pagan gods) are grammatically singular, not just for controlling verbs but for adjective agreement.
Any other languages, IE or not, with a similar rule?

