How would you express something being plural in sumerian? Would there be a special suffix that you would add onto a word to denote that there's more than one (i.e sons, daughters, etc.)
Hello! Plurality in Sumerian is a little more complicated than you might at first expect.
For person nouns, like son/daughter or the like, there is a plural suffix -(e)ne. It appears as -ene after a consonant (ninene "sisters") and just -ne after a vowel (dumune "children"). However, this only appears in certain cases, like the ergative case (subject of a transitive sentence); it doesn't appear in the absolutive case (the base case), in which case plurality is generally unmarked on the noun, but can be indicated by verb conjugation instead (dumu shir "the child sings", dumu shiresh "the children sing").
And -(e)ne can't be used at all for non-person-class nouns, like objects, plants and animals, ideas, etc. Instead, plurality is most often just implied: ab "cow" or "cows". You can pluralize by reduplicating the noun, i.e. saying it twice, but this generally emphasizes the plurality in some way. So abab would mean "lots of cows". (This type of pluralization is also used occasionally for person nouns - dumudumu "numerous children" - but I wouldn't use it if I could instead use -(e)ne).
There are a few other ways to imply plurality, like specific adjectives (abhia is "various cows", since you can't have *"various cow"), but in this case the noun is grammatically treated as a singular. And you can always pluralize with an explicit number, like ablimmu "four cows". I hope that helps, and if you have a contextual sentence for me to translate, let me know!