In a similar way to
みたい,
ようだ is used when making observations about something in Japanese. This 助動詞(じょどうし) (auxiliary verb) is used to express three primary things.
たとえ - Using (A) as an example to highlight the way that (B) looks/is acting.
推定(すいてい) - Using (A) as a reason for an assumption made about (B).
例示(れいじ) - Presenting (A) as an example of what (B) is.
ようだ is usually based on direct information/experience, and shows that the speaker has high confidence in what they are saying. It may also frequently appear in its kanji form, 様(よう)だ.
ようだ can be used with any verb,
い-Adjective,
な-Adjective, or noun. However, it requires な before it when used with
な-Adjectives, or
の when used with nouns.
-
ここに大(おお)きなビルが出来(でき)るようだ。
It seems like a big building will be made here.
-
あそこのプールは深(ふか)い様(よう)だ。
It seems like the pool over there is deep.
-
彼(かれ)は明日(あした)のテストに自信(じしん)があると皆(みんな)に言(い)っているが、本当(ほんとう)は不安(ふあん)なようだ。
He is telling everyone that he is confident about the test tomorrow, but it seems like he is actually worried.
-
ヨーダは宇宙人(うちゅうじん)のようだ。
Yoda appears to be an alien.
Although
ようだ and
そうだ are often used in similar situations,
そうだ shows that the speaker has a lot less confidence in their statement than
ようだ. Because of this,
ようだ is a much better choice when stating things that are obvious/observable by anyone.
ようだ is considerably more formal than みたい, and is therefore less common in casual conversation.