~ようだ

That's a great question! Both express that something 'seems' or 'appears,' but they get their information from different sources.

~ようだ (~you da) is used when you're making a judgment based on your own observation or general knowledge. Think of it as a personal inference.
Example: 外は雨が降っているようだ。(Soto wa ame ga futte iru you da.) - It seems like it's raining outside (because I saw wet ground or heard rain).

~そうです (~sou desu) is used when you're reporting something you've heard from someone else (hearsay) or when you're making a judgment based on immediate visual cues that directly show a state or condition (like a cracking glass 'looks like' it's about to break).
Example: 彼は来ないそうです。(Kare wa konai sou desu.) - I heard he's not coming.
Example: このケーキは美味しそうです。(Kono keeki wa oishisou desu.) - This cake looks delicious (based on its appearance).

Absolutely! The great thing about ~ようだ is its versatility. You can use it with verbs, i-adjectives, na-adjectives, and nouns, but the conjugation before ~ようだ changes slightly.

Verbs: Plain form (dictionary form, nai form, ta form) + ようだ
Example: 彼が来るようだ。(Kare ga kuru you da.) - It seems he's coming.

i-adjectives: i-adjective + ようだ
Example: この本は面白いようだ。(Kono hon wa omoshiroi you da.) - This book seems interesting.

na-adjectives: na-adjective + な + ようだ
Example: 彼は元気なようだ。(Kare wa genki na you da.) - He seems healthy/energetic.

Nouns: Noun + の + ようだ
Example: 夢のようだ。(Yume no you da.) - It's like a dream.

This is a common point of confusion for learners! Both mean 'it seems/looks like,' but there's a nuance.

~ようだ (~you da) is generally considered more formal and objective. It implies a conclusion drawn from solid evidence or observation. It's often used in writing or more formal speech.
Example: 彼の話は本当のようだ。(Kare no hanashi wa hontou no you da.) - His story seems to be true (based on evidence).

~みたいだ (~mitai da) is more casual and subjective. It implies a more personal or impressionistic feeling, often used in spoken Japanese. It can also imply a stronger comparison, like 'X is like Y.'
Example: 彼の話は本当みたいだ。(Kare no hanashi wa hontai mitai da.) - His story seems true (more of a feeling).
Example: 彼女は天使みたいだ。(Kanojo wa tenshi mitai da.) - She's like an angel.

Yes, absolutely! While its primary meaning is 'it seems/appears,' ~ようだ can also be used to express a comparison, meaning 'as if' or 'like' something. This is particularly common with nouns.

Example: 彼は子供のような笑顔だ。(Kare wa kodomo no you na egao da.) - He has a smile like a child's.
Example: まるで夢のようだ。(Maru de yume no you da.) - It's just like a dream.

~ようだ is quite flexible and changes its ending depending on its grammatical function in a sentence. Let's break down the common forms:

ようだ (you da): The plain, dictionary form. Used in casual speech or to end a sentence.
Example: 明日は晴れのようだ。(Ashita wa hare no you da.) - It seems like it will be sunny tomorrow.

ようです (you desu): The polite form. Used in polite speech or writing.
Example: 明日は晴れのようです。(Ashita wa hare no you desu.) - It seems like it will be sunny tomorrow.

ように (you ni): Functions like an adverb, modifying a verb or adjective. Means 'so that,' 'in such a way that,' or 'like.'
Example: 日本語が話せるようになるには、たくさん練習する必要がある。(Nihongo ga hanaseru you ni naru ni wa, takusan renshuu suru hitsuyou ga aru.) - In order to be able to speak Japanese, you need to practice a lot.

ような (you na): Functions like an adjective, modifying a noun. Means 'like a...' or 'such as...'.
Example: 彼は先生のような人だ。(Kare wa sensei no you na hito da.) - He is a person like a teacher.

To make ~ようだ negative, you typically conjugate the word *before* ようだ into its negative plain form.

Verbs: Negative plain form + ようだ
Example: 彼が来ないようだ。(Kare ga konai you da.) - It seems he's not coming.

i-adjectives: Remove the final 'i' and add 'kunai' + ようだ
Example: この本は面白くないようだ。(Kono hon wa omoshirokunai you da.) - This book doesn't seem interesting.

na-adjectives: Add 'de wa nai' + ようだ
Example: 彼は元気ではないようだ。(Kare wa genki de wa nai you da.) - He doesn't seem energetic.

Nouns: Noun + で はない + ようだ
Example: それは夢ではないようだ。(Sore wa yume de wa nai you da.) - That doesn't seem like a dream.

Generally, no. ~ようだ is used to express a judgment or inference about external situations, events, or other people's states. It's not typically used to express uncertainty about your own direct actions or intentions, as you would usually know your own plans.

If you want to express uncertainty about your *own* actions, you might use phrases like:
~と思います (~to omoimasu) - I think I will...
~かもしれません (~kamoshiremasen) - I might...

While 'it seems' and 'it appears' are very common translations for ~ようだ, it's good to remember that the best English translation can vary depending on the context. Sometimes it might be better translated as 'it looks like,' 'it sounds like,' 'it feels like,' or even 'it's likely that.' The core meaning, however, remains an inference based on observation or information.

Example: 誰か来たようだ。(Dareka kita you da.) - It sounds like someone came (because I heard a noise).

Not necessarily a *high* degree, but it implies a reasonable inference based on available information or observation. It's stronger than a simple guess but leaves room for the possibility that the perception might be wrong. It's about a 'reasonable assumption.'

For a higher degree of certainty, you might use more direct statements or other grammatical structures. For less certainty, you might use ~かもしれない (~kamoshirenai), which means 'might' or 'may'.

Yes, it can! When used in questions, ~ようだ often expresses a softer, more indirect way of asking for confirmation about a perceived situation, or it can be used to ask if something 'seems' a certain way to the listener.

Example: 彼は疲れているようですね？(Kare wa tsukarete iru you desu ne?) - He seems tired, doesn't he?
Example: この道は広くなったようだね？(Kono michi wa hiroku natta you da ne?) - This road seems to have gotten wider, hasn't it?