na-adjective, noun which may take the genitive case particle 'no', noun
inarticulate; slow of speech; tongue-tied
Describes a person who has difficulty expressing themselves smoothly; often implies a natural, unpolished way of speaking rather than a temporary state. Can be used as a noun or adjectivally.
He is slow of speech, but what he says is always profound.
Even an inarticulate person can learn to speak well with practice.
Composed of 訥 (stutter, slow of speech) and 弁 (speech, dialect). The exact historical derivation is uncertain, but the word has been used in literary Japanese to describe inarticulateness.