「なんとなく」和「なんだか」都可做词组和副词用。用作词组时两者不可替换。用作副词时,两者分别存在3个和2个义位。在表达其中的一个义位时可相互替换,但是存在细微的语义差别。前者侧重在说话者的心理感觉及情绪的表达,而后者侧重在说话者的主观情绪、心理感觉由某种原因引发,但原因不明。 Both “na na と na ku” and “na na da ka” can be used as phrases and adverbs. Both are irreplaceable when used as a phrase. When used as adverbs, there are three and two semantic bits respectively. In the expression of one of the vbs can be replaced with each other, but there are subtle semantic differences. The former focuses on the speaker’s psychological and emotional expression, while the latter focuses on the speaker’s subjective mood, psychological feeling triggered by some reason, but the reason is unknown.