Berean Study Bible (BSB) - Isaiah 33:19 >

You will no longer see the insolent, a people whose speech is unintelligible, who stammer in a language you cannot understand.

Jewish Publication Society of America Version (JPS1917) - Isaiah 33:19 >

Thou shalt not see the fierce people; a people of a deep speech that thou canst not perceive, of a stammering tongue that thou canst not understand.