sou そう

In Japanese, sou そう means "like that," "that's right," "it seems," or "I heard from someone that" depending on what function of the word is being used in a given sentence.

• Pronoun
• Suffix
• Interjection

Pronoun

Before a verb, sou そう is part of the kou, sou, aa, dou こう, そう, ああ, どう set of adverbial kosoado words.

• sou omou
  そう思う
  To think that way.
• sou shita
  そうした
  To have done that way.
  To have done so.

Suffix

After a word, it's the sou そう suffix, meaning "seems" or "so I heard" depending on how it's attached to other words.

• oishi-sou da
  美味しそうだ
  Seems delicious.
• oishii-sou da
  美味しいそうだ
  I heard it's delicious.
• oishi-sou na keeki
  美味しそうなケーキ
  A cake that seems delicious.
• oishi-sou ni taberu
  美味しそうに食べる
  To eat it in a way it seems delicious.
• shini-sou da
  死にそうだ
  It seems [he] will die.
• shinda-sou da
  死んだそうだ
  I heard [he] died.
• genki-sou da
  元気そうだ
  Seems lively.
• genki da-sou da
  元気だそうだ
  I heard [he] is lively.

Interjection

Alone in a phrase, it's the sou そう interjection, which means simply "so." And by alone I mean just it, the optional copula, sentence-ending particles, nominalizers or whatever other expressions, of course.

• sou そう
  sou da そうだ
  sou desu そうです
  sou desu yo そうですよ
  sou desu wa そうですわ
  sou yo そうよ
  sou da ze そうだぜ
  sou da zo そうだぞ
  sou da mon そうだもん
  sou da mono そうだもの
  sou de aru そうである
  sou de arimasu そうであります
  sou de arinsu そうでありんす
  sou degozaru そうでござる
  sou degozaimasu そうでございます
  It's so!
  That's right!
• sou na そうな
  sou ne そうね
  sou da na そうだな
  sou da ne そうね
  sou da mon na そうだもんな
  sou da mon ne そうだもんね
  Yeah.
  You're right.
  Isn't it so?
• sou ka そうか
  sokka そっか
  It's so, huh?
  I see.
• sou ka? そうか？
  sou desu ka? そうですか
  Is that so?
• sou darou そうだろう
  sou desho そうでしょ
  That's right, isn't it?
• sou de arou? そうであろう？
  sou deshou ka? そうでしょうか？
  Is that right?
• sou ka na? そうかな？
  sou ka ne? そうかね？
  Is that right, I wonder?
• sou nanda yo そうなんだよ
  sou na no da そうなのだ！
  sou na no desu そうなのです
  sou na no desu wa そうなのですわ
  sou nandesu そうなんです
  sou nandesu yo そうなんですよ
  Yeah, that's right!
• sou da tte そうだって
  sou da tte ba そうだってば
  sou da tte ba yo そうだってばよ
  I'm saying it's so!
• sou ni kimatteru! そうに決まってる！
  Of course it's so!

In essence this is the same meaning as the pronoun, except it isn't modifying a verb.