Isaiah 33:19

“When Israel came out of Egypt, the house of Jacob from a people of foreign tongue,”

Relates to the theme of understanding language and being delivered from foreign oppressors.

““I am bringing a nation against you from afar, people of Israel,” declares the LORD. “It is an enduring nation, a nation whose language you do not know, whose speech you do not understand.”

Connects to the inability to understand the language of a foreign nation.

“You are not being sent to a people of obscure speech and strange language, but to the people of Israel— not to many peoples of obscure speech and strange language, whose words you cannot understand. Surely if I had sent you to them, they would have listened to you.”

Links to the theme of foreign languages and understanding.

“For anyone who speaks in a tongue does not speak to people but to God. Indeed, no one understands them; they utter mysteries by the Spirit.”

The inability to understand a foreign tongue.

“So if the whole church comes together and everyone speaks in tongues, and inquirers or unbelievers come in, will they not say that you are out of your mind?”

Addresses the problem of those unfamiliar with a language not understanding it.