without or deprived of the use of speech or words; "inarticulate beasts"; "remained stupidly inarticulate and saying something noncommittal"; "inarticulate with rage"; "an inarticulate cry"
based on custom rather than documentation; "an unwritten law"; "rites...so ancient that they well might have had their unwritten origins in Aurignacian times"- J.L.T.C.Spence