The Greek that is translated in English as “brotherly love” (also: “mutual love” and others) is translated in Waama as “love each other as children of the same mother.” Like many languages, Waama has no generic term for “brother” and sister, just “older brother” or “younger brother.” At first, “love each other as children of the same father” seemed to fit but since the Waama live in a polygamous society, brothers of the same father with different mothers often don’t get along unlike maternal siblings. (Source: Kathrin Pope in Holzhausen / Riderer 2010, p. 54)
In the German New Testament translation by Berger / Nord (publ. 1999) it is translated with geschwisterliche Liebe or “love between siblings.”
In Romans 12:10 the Protestant Mandarin Chinese Union Version and the Catholic Sigao version translate this with a historical Chinese idiom: huíxīn zhuǎnyì (相親相愛 / 相亲相爱) or “close and loving.” (Source: Toshikazu S. Foley in Hong Kong Journal of Catholic Studies, 2011, p. 45ff.)