“At that time,

I will change

The speech of the people

To a pure speech.

All of them

May call

On the name of Yahweh.

They will serve him

With one accord.

From beyond the rivers

Of Ethiopia,

My suppliants,

My scattered ones,

Shall bring my offering.”

Yahweh, via Zephaniah, seems to indicate that there will be a universal conversion to Yahweh.  He was going to change the varieties of speech into one pure language, so that all would call upon the name of Yahweh and serve him together.  This was a very utopian ideal.  All his scattered people would come from beyond the Ethiopian rivers to bring offerings to him.