Albert Barnes Commentary Isaiah 28:11

"Nay, but by [men of] strange lips and with another tongue will he speak to this people;" — Isaiah 28:11 (ASV)

For - This verse is to be understood as a response to what the complaining and dissatisfied people had said, as expressed in the previous verse. God says that he will teach them, but this teaching will be by another tongue—a foreign language in a distant land. Since they refused to heed the messages he sent to them, which they regarded as suitable only for children, he would teach them in a manner that would be much more humiliating; he would make use of the barbarous language of foreigners to bring them to the true knowledge of God.

With stammering lips - The word used here is derived from a verb (לעג lâ‛âg), which means to speak unintelligibly: especially to speak in a foreign language, or to stammer; and then to mock, deride, laugh at, scorn (Proverbs 1:26; Proverbs 17:5; Psalms 2:4; Psalms 59:9; Job 22:19). Here it means in a foreign or barbarous tongue; and the sense is, that the lessons God wished to teach would be conveyed to them through the language of foreigners—the Chaldeans. They would be removed to a distant land, and there, in hearing a strange speech, in living long among foreigners, they would learn the lesson which they refused to learn when addressed by the prophets in their own land.