異口同音

いく　どうおん
iku douon

Today's yo-ji jukugo is so straightforward and easy to understand that the only thing I can possibly do to make it more interesting/challenging is throw a bunch of synonymous 四字熟語 at you. Different phrases, but they're saying the same thing. How appropriate.

Before that though, while I'm still basking in how clever I am, let's check the definition.

Definition:
多くの人が、同じ言葉を口にすること。また、多くの人が一致して同じ意見をいうこと。
Translations:
1. In unison
2. Unanimously

The kanji make this one clear enough: different mouths, same sound.

SYNONYM TIME:

異口同声 (いくどうせい；ikudousei) and 異口同辞 (いくどうじ; ikudouji) get away with just switching out the last kanji, to become　"different mouths, same voice" and "different mouths, same language" respectively. But if you're a Rikai-chan user, you'll notice that these don't enjoy the same recognition that 異口同音 does, so don't expect them to work well in conversation.

Then there's 衆目一致 (しゅうもくいっち; shuumokuicchi) which is used to mean a consensus of opinion, or something widely agreed upon, or widely admitted.

And we'll finish out with 満場一致 (まんじょういっち;manjyouicchi) which also means "unanimous."

Things that I'm paying close attention to:

• The reading of 異, which features in a handful of 1級 熟語.
• 衆, which also is important for 1級, in that it gets used a lot for things that are in the public arena, like politics and business, in which direction 1級 content tends to lean (you know, when they're not focused on video games).
• 一致, appearing in two of the synonymous yo-ji, used to mean "agreement," or "union." And coincidence. Not the 偶然 style coincidence, but an act of coinciding.

例文：

騙されやすい先生：先生は宿題があったと思っていたが、教室では異口同音に「なかった」と言われて、やはり出すのを忘れたみたい。
Easily-fooled teacher: I thought you had homework to hand in, but if EVERYONE in class is saying that there wasn't any, I guess I forgot to assign it!