Isaiah 33:19

You will see those arrogant people no more, those people of an obscure speech, with their strange, incomprehensible tongue.

Isaiah 28:11

With stammering lips and another tongue he will speak to this people.

Deuteronomy 28:49-50

Jehovah will bring a nation against you from far away, from the end of the earth, as the eagle swoops down, a nation whose language you will not understand,

Jeremiah 5:15

I am bringing a nation against you from afar, O house of Israel, declares Jehovah. It is an enduring nation. It is an ancient nation, a nation whose language you do not know. You cannot understand (comprehend) (make sense of) what they say.

2 Kings 19:32

This is what Jehovah said about the Assyrian king: 'He will not enter this city or shoot a single arrow against it. No soldiers with shields will come near the city. No siege mounds will be built around it.'

Ezekiel 3:5-6

I am not sending you to people whose language is hard to understand or difficult to speak. I am sending you to Israel.

Exodus 14:13

But Moses said to the people: Do not fear! Stand by and see the salvation of Jehovah. He will accomplish this for you today. The Egyptians whom you have seen today, you will never see them again forever.

1 Corinthians 14:21

It is written in the law: With men of other tongues and lips of foreigners I will speak to this people. Even then they will not listen to me, said Jehovah.

Treasury of Scripture Knowledge

Summary

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

Bible References

Shalt not

Exodus 14:13
But Moses said to the people: Do not fear! Stand by and see the salvation of Jehovah. He will accomplish this for you today. The Egyptians whom you have seen today, you will never see them again forever.
Deuteronomy 28:49
Jehovah will bring a nation against you from far away, from the end of the earth, as the eagle swoops down, a nation whose language you will not understand,
2 Kings 19:32
This is what Jehovah said about the Assyrian king: 'He will not enter this city or shoot a single arrow against it. No soldiers with shields will come near the city. No siege mounds will be built around it.'

Deeper

Isaiah 28:11
With stammering lips and another tongue he will speak to this people.
Jeremiah 5:15
I am bringing a nation against you from afar, O house of Israel, declares Jehovah. It is an enduring nation. It is an ancient nation, a nation whose language you do not know. You cannot understand (comprehend) (make sense of) what they say.
Ezekiel 3:5
I am not sending you to people whose language is hard to understand or difficult to speak. I am sending you to Israel.
1 Corinthians 14:21
It is written in the law: With men of other tongues and lips of foreigners I will speak to this people. Even then they will not listen to me, said Jehovah.