Jesus uses a number of uncommon words here. Two words he uses nowhere else, "oxen" and "fatlings." The word for "dinner" is only used twice. The word translated as "killed/butchered" is only used five times.
The word for "wedding" here and in throughout this parable, is plural. This word appears four times in the Septuagint, always translated into English as "feast," from a Hebrew word mištê (מִשְׁתֶּה), which means "feast." It is used more often in the NT, always referring to a wedding, but only in the plural in this parable. Since this refers only to one event (elsewhere a singular "lunch" is used to describe it) the word seems to mean the same in singular and plural coincidently, like our "nuptial," which is also used in the singular and plural.
Christ's Words in Matthew as a Guide to 40 Days of Prayer.