Observation: hearsay
んだって
V
い-Adj
な-Adj + な
N + な
+ んだって・んですって
Used to quote something that you heard in a casual conversation. Similar in the quotation sense to って, but here the nuance is that the information is new or unexpected.
Example
ワールドカップでアルゼンチンが勝したんだって! Argentina won the world cup! (you just saw it on TV but you were doing something else and are surprised)
と聞いた
Used for something you heard by someone identifiable: for example, you were told by someone. Mostly used formally.
Example
彼はバカと聞いた。 They say he’s an idiot (I’ve heard that he’s an idiot).
と言われている
Used when you heard something, but not from someone specifically identifiable: general knowledge, a rumour, etc. For nouns, だ is placed before. Mostly used formally.
Example
このレストランのカレーはおいしいだと言われています。 They say the curry of this restaurant is good.
そうだ
V (casual)
い-Adj
な-Adj + だ
N + だ
+ そうだ
Means “I heard that”. Do not confuse with そうだ (no stem modification). It is casual.
Examples
テストは難しいだそうだ。 The exam is said to be difficult.
ということだ
It is used for hearsay. Has a nuance of being sure of the validity. Can also be used for a meaning close to “this means”. More formal than そうだ. Can be used as ということだ or とのことだ. A more casual version is ってことだ.
Examples
専門家によると、今年の夏は最高暑くなるということです。 According to the experts, this summer will be the hottest ever.
Summing up
- んだって used for quotation, similar to って, when the information is new.
- と聞いた is used for something for something you heard from an identifiable speaker. Is mostly formal.
- と言われている is used for something for something you heard from an unspecified speaker. Is mostly formal.
- そうだ is used for hearsay and is casual.
- ということだ is used for hearsay, when the validity of the information is certain. More formal than そうだ.
によると・によれば
Means “according to”. Used with nouns. With verbs, ところ is added before.
Examples
天気予報によると今日は雪が降るようだ。 According to the weather forecast, it’s supposed to snow today.