"The cooks cook dinners."
Translation:Coqui cenas coquunt.
Noun endings are relatively consistent. For most nouns, if you know the declension and gender, you shouldn't have too much issue (assuming you are comfortable with how each case is used).
For first declensions in the accusative (the thing an action is being done to) plural, the ending is -as. -ae as a plural would be the nominative (the thing doing the action) and vocative (directly addressing the thing).