食べたそうだ vs. 食べそうだ, 静かだそうだ vs. 静かそうだ


I saw this as a comment on this question, [Why does そう in 「美味しいそう」 not mean
"seem" the way I think it
should?](https://japanese.stackexchange.com/questions/1994/why-
does-%E3%81%9D%E3%81%86-in-)「美味しいそう」-not-mean-seem-the-way-i-think-it-should,

and would love to understand the differences.

I am sure I will mangle the translation, so forgive me.

> 食べたそうだ Looks like he ate it.
>
> 食べそうだ Looks like he will eat it.
>
> 静かだそうだ I heard that it's quiet.
>
> 静かそうだ Seems quiet.

If anyone would be kind enough to explain the differences in meaning and
usage, I would greatly appreciate it. I didn't learn how to embed the quoted
question, so sorry again for that.




**The first そう** comes after 終止形 of verbs and adjectives. All 終止形 forms,
negatives, passives, causatives, present and past etc are possible.

This means "I hear(d)/read that... " (not looks/seems like as assumed in the
question).

> 彼は死んだそうだ I heard he died  
>  あのケーキは美味しいそうだ I hear that cake is declicious  
>  彼は嫌われていなかったそうだ They say he wasn't hated.

This そう is often listed as a particle, but it really behaves like a noun, and
is almost always followed by copula. It has no 連体形, i.e. 静かだそうな is
ungrammatical (unless な is the sentence-ending particle). Also, the following
copula is not used in the past tense, i.e. 静かだ(った)そうだった does not exist, but
静かだったそうだ does.

**The second そう** comes after the 連用形 of verbs and the stem of adjectives.
良い(いい) and 無い have irregular forms 良さそう and 無さそう. Negative verb forms ～ない
become ～なそう, but ～なさそう is often heard, although it's considered incorrect.

> 濃{こ}そう, 静かそう, 行きたそう, 食べなそう looks dense, seems quiet, looks like _sby_ wants
> to go, looks like _sby_ won't eat

The result of this is a na-adjective meaning "looks ..." or "seems ...". For
action and state-change verbs, it can also meen "about to ..." or "looks like
_sby_ will ...".

Being a na-adjective, this form can be used both in the 終止形 and 連体形 forms (and
negative forms etc.),

> 美味しそうなケーキ a delicious-looking cake  
>  このケーキは美味しそうだ this cake looks declicious
>
> 死にそうな人 a person (looking like he's) about to die  
>  彼は死にそうだ (he looks like) he's about to die

