I'm struggling here with that affectionate term used for girls/young ladies, "lass" or "lassie," the latter usually applied to younger girls. It's what plural to use. If you see a bunch of nine-year-old girls, especially in Scotland, you might say "Look at those lassies!" Logical, or does it sound like you're referring to a pack of collies? I saw that plural used in the Guardian this morning and it faintly rankled. But a bunch of mature young women might be "lasses," eh? Do we really need two separate plural spellings for a word that sounds identical? Every time I see "lassies" something visceral has me thinking that an ignorant mistake has been made...