From: Oromo, East Africa
Source: Oromo proverb; documented in Cotter, "Proverbs and Sayings of the Oromo People of Ethiopia and Kenya with English Translations" and Oromo proverb research (advocacy4oromia.org). Original text, translation ("What the tongue breeds or generates, the bull could not") and explanation from Megersa Regassa Tolasa and Dejene Gemechu Chala, "Oromo Proverbs and Proverbial Expressions in the Customary Judicial System in Ethiopia," Journal of Ethnology and Folkloristics 13(2), 2019; the saying was earlier shown here with "the bull's horns", which that original does not contain
The source explains it: a sharp tongue has the power to generate bad or humiliating words that possibly cause conflict or punishment from God
. The wording of the meaning is ours.