noun
everyday language; common parlance; vernacular
Refers to the ordinary words and expressions used in daily conversation, as opposed to technical, literary, or formal language.
専門用語ではなく、日常語で説明してください。
Please explain it in everyday language, not technical terms.
この小説は日常語で書かれていて
This novel is written in everyday language and is easy to read.
俗語 means slang or vulgar language, which is a subset of informal language, whereas 日常語 is neutral and simply means everyday words.
Compound of 日常 (にちじょう, 'everyday') and 語 (ご, 'language, word').