noun
spoken language; spoken words
Refers to language as it is spoken, as opposed to written language. Often contrasted with 書き言葉 (written language).
See also: 口頭語
口言葉と書き言葉は違う。
Spoken language and written language are different.
彼の口言葉はとても丁寧だ。
His spoken words are very polite.
noun
A broader, somewhat rare use referring to language in general, often in contrast to non-verbal communication. More commonly expressed as 言語.
口言葉は人間だけのものではない。
Language is not unique to humans.
Compound of 口 (mouth, speech) and 言葉 (word, language). The exact historical derivation is uncertain, but the word has been used to distinguish spoken from written language.