'Obscure' in the Bible

You will not see [the] insolent people, [the] people {whose language is too obscure to understand}, [whose] stammering of tongue {cannot be understood}.

For you are sent to the house of Israel, not to a people {of obscure speech} and {of a difficult language},

[and] not to many nations {of obscure speech} and {a difficult language} {whose words} you do not understand, [for] if I had sent you to them they would have listened to you.