Passive sentence construction


I came across this sentence:

> 全員に作業が割り当てられました。

In a passive sentence, the particle に marks the action doer, and that means
the sentences should translate to

> "Work was assigned (to me) by all members"

On Anki and Google Translate, the correct translation is

> "Work was assigned to all members"

Why is the latter correct instead of the former?




The particle に can mark the agent performing the action in a passive sentence
_if_ that agent is specified, but 1) the particle に can also do lots of other
things and 2) in some passive sentences (including this one) the agent is not
specified.

In this case, に isn't marking the agent or “action doer” (the person or people
_by_ whom the work was assigned), but the indirect object – that is, the
people _to_ whom the work was assigned or (to use a translation that I think
works a little better here) _to_ whom the different tasks were allocated. This
に would still be there even if you rephrased the sentence using the active
voice, as in 社長が全員に作業を割り当てました (“The president of the company allocated tasks
to everyone”).

As for why “Work was assigned (to me) by all members” isn’t a very likely
translation for this sentence, as I’ve indicated above, the verb 割り当てる doesn’t
simply mean “assign,” but is more like “allocate,” “parcel out,” or
“apportion” – the idea is not just that something is being assigned, but that
it is being divided (割る) into parts which are assigned (当てる) to different
people. Thus, for this verb it’s generally much more natural for the agent
_performing_ the action to be singular and the indirect object _receiving_ the
action to be plural, rather than the reverse. (Although as in English it's not
impossible for the entity performing the allocation to be plural, and in some
contexts you could say something like 私に割り当てられた作業 to mean “the tasks that were
allocated to me.”)

