Oh, you mean word endings for plurals, well those depend on the gender and the singular word ending. They can be a bit confusing, because they’re not always regular like local -> locaux, but naval -> navals. You have that in other languages too, even in english, like goose -> geese, but moose -> moose, mouse -> mice, house -> houses, and so on.
Obviously houses are owned by someone, either people, corporations, public entities. Home ownership usually refers to the share of people owning the homes they live in.