also: ためぐち
casual speech; informal language; peer language
Refers to speaking in a casual, informal manner, typically used among close friends or equals, without honorifics or polite forms. Often contrasted with 敬語 (keigo).
It's rude to use casual speech with your seniors.
彼とは仲がいいから、いつもタメ口で話している。
We're close, so we always talk in casual language.
I ended up speaking casually to him even though we'd just met.
I always talk casually with my friends.
You should stop speaking casually to your boss and use polite language instead.