んだってI heard that, He or She said that

Both ときいた and んだって express hearsay, but with different nuances and formality. ときいた means 'I heard (A).' and conveys information directly heard by the speaker, e.g. 高いときいた ('I heard it was expensive.'). In contrast, んだって is casual and adds an explanatory nuance, like 'They say (A).' or 'I heard that (A).', e.g. 高いんだって ('They say it's expensive, you know.').

Both expressions involve だって, but their usage differs. んだって appears at the end of a sentence and means 'I hear (A)' or 'they say (A)', with an explanatory nuance added by ん. In contrast, だって is more flexible. It can appear at the beginning, middle, or end of a sentence, and has several meanings. It can function as a casual 'because', 'even though', or 'they say (A)', depending on context.

Both express hearsay, but with different tone and usage. んだって is very casual, often used in everyday conversation, and carries an explanatory tone due to んだ, e.g. 明日休みなんだって ('They said tomorrow's a day off, you know.') そうだ is more neutral and indirect, with no explanatory nuance, e.g. 明日休みだそうだ ('I heard tomorrow's a day off.')

って (a contracted form of と) is a casual quoting particle used to mark direct or indirect speech, thoughts, feelings, or to introduce a topic. んだって, which combines って with the explanatory ん・の, is used to express 'I heard' or 'He/she/they said.' While って can follow any word, んだって requires な before な-Adjectives or nouns.

These two expressions are similar in that both can serve as casual expressions of hearsay, i.e. 'they say (A)' or 'I hear (A)'. The difference is that んだって has a slightly more explanatory and emphatic nuance due to the presence of ん, while とか has an uncertain or non-specific tone, i.e. 'I hear (A) or something', because of the presence of the question particle か.

んだって and らしい ① both convey information from another source, but with different nuances and levels of formality. らしい ① suggests hearsay with a nuance of certainty, indicating the speaker believes it to be true, e.g. 'Apparently it's (A).'. In contrast, んだって is highly casual and includes an explanatory nuance, similar to 'He/she/they said/say (A), you know.'.