The phrase that is translated in English as “fattened calf” is translated in Fuyug as “the calf full of grease.” (Source: David Clark)
In some Hindi translations it is translated as mota pashu (मोटा पशु) or “fattened animal” to avoid the traditionally negative association with slaughtering cows. (In the case of पवित्र बाइबिल, the Common Language Hindi Bible, a footnote is added that says “In the original text: ‘calf.'”)
The now commonly-used English idiom “kill the fatted calf” (meaning having a celebration for someone who’s been away a long time) was first coined in 1526 in the English New Testament translation of William Tyndale. (Source: Crystal 2010, p. 277)
For other idioms in English that were coined by Bible translation, see here.
Many languages distinguish between inclusive and exclusive first-person plural pronouns (“we”). (Click or tap here to see more details)
The inclusive “we” specifically includes the addressee (“you and I and possibly others”), while the exclusive “we” specifically excludes the addressee (“he/she/they and I, but not you”). This grammatical distinction is called “clusivity.” While Semitic languages such as Hebrew or most Indo-European languages such as Greek or English do not make that distinction, translators of languages with that distinction have to make a choice every time they encounter “we” or a form thereof (in English: “we,” “our,” or “us”).
For this verse, translators typically select the inclusive form (including the slaves).
Source: Velma Pickett and Florence Cowan in Notes on Translation January 1962, p. 1ff.
Following are a number of back-translations of Luke 15:23:
Nyongar: “Then go and get the best young bullock and kill it. We will eat and drink with happiness. Let’s celebrate!” (Source: Warda-Kwabba Luke-Ang)
Uma: “After that, you catch a fat calf and slaughter it. We will eat with great joy [lit., glad-glad]” (Source: Uma Back Translation)
Yakan: “Then go and get the calf that we (incl.) have been fattening and butcher it. We (incl.) will feast and have a celebration.” (Source: Yakan Back Translation)
Western Bukidnon Manobo: “And go and get that young cow that I’ve been fattening, and butcher it because we will eat and be happy.” (Source: Western Bukidnon Manobo Back Translation)
Kankanaey: “Then go get the fat cow calf so that you will butcher it so that we will eat/feast-on it and be-happy,” (Source: Kankanaey Back Translation)
Tagbanwa: “Also hurry up and fetch that young cow which has been fattened and butcher it, for we (incl.) will have a feast and celebrate.” (Source: Tagbanwa Back Translation)
kai phagontes euphranthōmen ‘and let us eat and enjoy ourselves, or, celebrate,’ both acts occurring together. For euphrainomai cf. on 12.19.
Translation:
The fatted calf, or, ‘the fattest/best calf,’ “the prize calf” (Good News Translation); An American Translation has an active finite form, “the calf we are fattening” (and in vv. 27 and 30, “the calf he has, resp. you have, been fattening”). Calf, or, ‘young bull,’ cf. on “ox” in 13.15; the generic ‘beast’ is sometimes a sufficient designation, e.g. in East Nyanja, Lomwe, Yao. If the whole concept is foreign to the receptor culture one may say, ‘the very best food I, or, we (inclus.), keep in supply.’
Eat and make merry, or ‘let-us(inclus.)-eat having a feast’ (Tae’), or in a single verb, ‘let-us(inclus.)-be-feasting’ (Toraja-Sa’dan); and cf. 12.19.
Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.