Not to many people of a strange speech and of an hard language, whose words thou canst not understand. Surely, had I sent thee to them, they would have hearkened unto thee.
Not to many people. It would have increased the difficulty had he been sent not merely to one but to "many people," differing in tongues, so that the missionary would have needed to acquire a new tongue for addressing each. The later mission of the apostles to many peoples, and the gift of tongues for that end, are foreshadowed (cf. 1 Corinthians 14:21 with Isaiah 28:11).
Had I sent thee to them, they would have hearkened - (Matthew 11:21; Matthew 11:23).