Core — expected in every language; an empty cell is an error and the
build refuses it. Filling in — a core word still being worked through. An empty cell here
is a real gap, and this is where the work is. Partial 🧪 — the concept itself is not universal. A language that does
not conventionalise a rooster's crow has no word for it, so an empty cell is
the correct answer and a low percentage is not a gap. Historical languages are counted apart, because a gap there often is not
one. Old Irish has no word for Wi-Fi, and Sumerian's vocabulary is only as
complete as its surviving corpus — so an empty cell can mean “not attested”,
which is never what it means for a living language.