Should we use sacred names?
Key Verse:  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]

This question is asked frequently because there are those who teach we should only address or talk about God and Jesus with a sacred name and that the true believers would know them and use them accordingly. This belief is based on the thought that Hebrew is a pure language, and that it was used before Babel, but Scripture does not support this thinking.  Let us turn to the book of Genesis.
Go to, let us go down, and there confound their language, that they may not understand one another's speech.  [Genesis 11:7]
No one language survived as perfect or pure, otherwise believers would have been told use this language or that language. Instead, the Apostle Paul tells us the following in Romans.
Likewise the Spirit also helpeth our infirmities: for we know not what we should pray for as we ought: but the Spirit itself maketh intercession for us with groanings which cannot be uttered.  [Romans 8:26]   
What are we to conclude?  At this time, there is no pure language, and our prayers are being translated, as it were, by the Holy Spirit back to God in a pure language which we do not know and cannot utter or speak.

Another area of discussion is where Moses is told to tell the children of Israel the following:  
And Moses said unto God, Behold, when I come unto the children of Israel, and shall say unto them, The God of your fathers hath sent me unto you; and they shall say to me, What is his name? what shall I say unto them?  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.  And God said moreover unto Moses, Thus shalt thou say unto the children of Israel, The LORD God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob, hath sent me unto you: this is my name for ever, and this is my memorial unto all generations.  [Exodus 3:13-15]
Here we learn of the I AM THAT I AM or YHWH, the tetragrammaton for I AM THAT I AM.  YHWH is an unpronounceable group of letters, without vowel points, that represents I (Y) AM (H) THAT (W) AM (H). What man has tried to do is make the unpronounciable, pronounceable by adding what they believe to be acceptable vowels, so we (man) can say this name.  YHWH is not as much a name but letters representing an existing being that causes things to be or exist. Remember when Jesus was speaking to the Pharisees in John, He spoke these words:
Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I am.  [John 8:58]
Further study reveals that the patriarchs did not know something that people today claim to know - the sacred name.  If anyone would have known, it would have been Abraham, Isaac and Jacob.
And I appeared unto Abraham, unto Isaac, and unto Jacob, by the name of God Almighty, but by my name JEHOVAH was I not known to them. [Exodus 6:3] 
Jehovah is another use of YHWH. There was no J in the Hebrew alphabet. Here we have YHWH that became JHVH and then by adding vowel points to make JHVH pronounceable - thus Jehovah.  People take the YHWH and add vowels to make it become Yahweh.  This, they say, is the way we must pronounce God's name as a pure name.

Lastly we are told in the following in Zephaniah:  
For then will I turn to the people a pure language, that they may all call upon the name of the LORD, to serve him with one consent. [Zepaniah 3:9]
In the previous verse, we read:
Therefore wait ye upon me, saith the LORD, until the day that I rise up to the prey: for my determination is to gather the nations, that I may assemble the kingdoms, to pour upon them mine indignation, even all my fierce anger: for all the earth shall be devoured with the fire of my jealousy.  [Zephaniah 3:8]
We can see that the time when the pure language is restored will take place after the battle of Armageddon, which is the Seventh Plaque of the Seven Last Plagues.  God's wrath is stored up in the Seven Last Plagues, and they will be poured out upon the earth after the resurrection of the saints.

A "pure language" will be returned, meaning we do not have one now, and in Revelation, we read:  
His eyes were as a flame of fire, and on his head were many crowns; and he had a name written, that no man knew, but he himself. [Revelation 19:12]
 This verse tells us that when Jesus returns he had a name written, THAT NO MAN KNEW but He Himself.  If we believe what these verses tell us, how could we possibly know His name now?