DEAD languages are those, which were once spoken by different nations, but have now ceased to be in general use. While any language is in common use, it is subject to changes, and each generation gives a different shade of meaning to some of its words; but when any nation adopts another language, the old one goes out of use, and is no longer subject to change.

The languages in which the Bible was originally written, were once generally spoken in Bible countries, but are not now in general use, hence are not subject to change; so that whatever a word meant when those languages ceased to be spoken, it means now. All will see how necessary this is to a proper understanding of the Bible. Had those languages continued alive, they would have been subject to change all the way along, and we should not now be able to know whether the Bible in its present form is the true word of God or not.

But what seems quite strange about this, is the fact that the Hebrew language, in which the Old Testament was written, went out of general use about the time the last of the prophets wrote, thus confining the meaning of the language to its acceptation at that time, and precluding the possibility of its corruption.

So with the New Testament. Soon after it was written in the Greek, that language ceased to be commonly spoken, and all its words were ever afterward to have the same meaning then attached to them.  In all this we can see the fulfillment of God's word. Isaiah says, 

"The grass withereth, the flower fadeth, but the word of our God shall stand forever," It shows, too, how careful the Lord has been to preserve the Bible to us free from corruption, that we may have faith in him, and confidence in his promises.