spoken language; colloquial speech
Refers to language as it is naturally spoken, including colloquial expressions, contractions, and informal grammar. Often contrasted with 書き言葉 (written language).
See also: 書き言葉
In spoken language, している often becomes してる.
この教科書は話し言葉の表現をたくさん紹介している。
This textbook introduces many colloquial expressions.
That expression changes when said in spoken language.
In Japanese, it's important to distinguish between spoken and written language.