"And God said unto Moses, I AM THAT I AM: and he said, Thus shalt thou say unto the children of Israel, I AM hath sent me unto you." -Exodus 3:14, KJV

The phrase I AM THAT I AM is a series of 3 Hebrew words: hâyâh 'ăsher hâyâh. Hâyâh literally means "to exist" (Strongs H1961). Further, this is an emphatic form, never a mere statement of existence. 'ăsher literally means that. God is literally saying that He is the One Who exists in such a way that it is notable (eternally and without sustaining power from any other being), and He repeats it. There is no other way to describe God other than to say, "He is what He is": God is God.

Even though I refer back to the original languages occasionally in Scripture, I do not do this to correct the KJV, only to clarify. I strongly believe that God Almighty supernaturally inspired His Word and preserved It through the ages in the Textus Receptus, and that It was preserved and even guided during its translation into English by devout men in the Authorized King James Version, and that all English translations other than the KJV have been translated from some form of the corrupted critical text and are not fully Scripture. I believe that the KJV is the accurate translation of the true Word of God, and that it needs no correction. However, I do believe that any time any work is translated from one language to another, some "flavors" of certain words get lost in translation, and this flavor can be regained [in some measure] from clarification, even though the word chosen is exactly correct and the closest equivalent the final language has.