Isaiah 33:19

Thou shalt no more see the fierce people, a people of a deeper speech than thou canst comprehend, of a stammering tongue that cannot be understood.

Isaiah 28:11

For with stammering lips and a strange tongue will he speak to this people;

Deuteronomy 28:49-50

Jehovah will bring a nation against thee from afar, from the end of the earth, like as the eagle flieth, a nation whose tongue thou understandest not;

Jeremiah 5:15

Behold, I bring a nation upon you from afar, house of Israel, saith Jehovah: it is a mighty nation, it is an ancient nation, a nation whose language thou knowest not, neither understandest thou what they say.

2 Kings 19:32

Therefore thus saith Jehovah concerning the king of Assyria: He shall not come into this city, Nor shoot an arrow there, Nor come before it with shield, Nor cast a bank against it.

Ezekiel 3:5-6

For thou art not sent to a people of strange language, and of difficult speech, but to the house of Israel;

Exodus 14:13

And Moses said to the people, Fear not: stand still, and see the salvation of Jehovah, which he will work for you to-day; for the Egyptians whom ye have seen to-day, ye shall see them again no more for ever.

1 Corinthians 14:21

It is written in the law, By people of other tongues, and by strange lips, will I speak to this people; and neither thus will they hear me, saith the Lord.

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
And Moses said to the people, Fear not: stand still, and see the salvation of Jehovah, which he will work for you to-day; for the Egyptians whom ye have seen to-day, ye shall see them again no more for ever.
Deuteronomy 28:49
Jehovah will bring a nation against thee from afar, from the end of the earth, like as the eagle flieth, a nation whose tongue thou understandest not;
2 Kings 19:32
Therefore thus saith Jehovah concerning the king of Assyria: He shall not come into this city, Nor shoot an arrow there, Nor come before it with shield, Nor cast a bank against it.

Deeper

Isaiah 28:11
For with stammering lips and a strange tongue will he speak to this people;
Jeremiah 5:15
Behold, I bring a nation upon you from afar, house of Israel, saith Jehovah: it is a mighty nation, it is an ancient nation, a nation whose language thou knowest not, neither understandest thou what they say.
Ezekiel 3:5
For thou art not sent to a people of strange language, and of difficult speech, but to the house of Israel;
1 Corinthians 14:21
It is written in the law, By people of other tongues, and by strange lips, will I speak to this people; and neither thus will they hear me, saith the Lord.