silent -
implied by or inferred from actions or statements; "gave silent consent"; "a tacit agreement"; "the understood provisos of a custody agreement"
inarticulate,
unarticulate 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"