Subject and Object in a 太ってる sentence


I've never really had to think about object vs subject in native English since
it's always come naturally for me, and I barely remember grammar studies when
I was a child.

It seems to be important to mark subject and object properly in Japanese so
I'm trying to understand how it works in the following example:

> ばいきんまんを太った。

Is Baikinman the object here since "got fat" was the action that happened to
him? Baikinman is the receiver of the action of getting fat?

> ばいきんまんが太った。

Or is Baikinman considered the subject? If that's the case then what would be
the object here? If nothing is acting on him becoming fat?

Can someone explain this in simple terms for me?




If you're having trouble with subject, object and transitivity then 太る is
probably not a good verb to start with since it does not map to a verb in
English.

太る is an intransitive verb (does not take an object) which means 'to become
fat'. Putting this in た form means that the process of becoming fat is
complete, i.e. 'got fat'.

I think the fact that you translate this with 'got' may be confusing you
because in the sentence 'X got Y', X is the subject and Y is the object. But
this 'got' has a different meaning from the one you are using above. When you
say 'I got soup' you mean 'I obtained soup'. When you say 'I got fat' you
don't usually mean 'I went out and bought some fat'. You mean 'I became fat'
and that 'became fat' is all neatly swept up in the single word 太った so there
is no place for an object.

