No major difference exists between the Masoretic text and the Old Testament portion of most modern translations. The Orthodox Jewish Bible says almost exactly the same translation as does, for example, the New International Version (which uses the MT as source). To compare the verses, see here: http://www.biblegateway.com/passage/?search=Isaiah+14&version=OJB So, there isn't a change in Isaiah 12:14. They both say the same things in Hebrew, Orthodox Bible (mixed English and Hebrew based on the MT) and say the NIV or NASB, after allowing for minor variance in translations. . Lior may have gotten confused with Isaiah 14:4, which indeed mentions King of Babylon, but it's the same in both the MT and the NIV. I can't find many differences between the Orthodox Bible, and the OT in the NIV. Those which exist are typically a translator's editorial choice, explained in a footnote. I use my Biblica Hebraica (Hebrew Masoretic text) for study; it's rare to find differences.
How can a translator translate? I mean I speak English. Another speaks Spanish. Someone translate, does he not understand? Yes. If you want to go back to original version, or writings you can. Good for studies or if you want to become some pastor. I can tell you most and very little is lost in translation. King James and NIV are the two I think are accurate. NIV is put in language we use today. No thee, and thou. NKJV is also put in language we use today.
Isaiah 14:12 says, "How art thou fallen from heaven, O day-star, son of the morning! How art thou cut to the ground, that didst cut lots over the nations!", in the best English translation I know, based on the Hebrew MT. The MT is highly reliable, and although we do not have manuscripts earlier than the 1st century, the MT is consistent with the Dead Sea scrolls. Many versions used by Christians are based on the corrupted LXX, and some of them such as the KJV have a made up Lucifer that is not mentioned on the original, and they change the text from being about the King of Babylon to being about the Satan. That's of course rubbish. The text uses the metaphor of the planet Venus to describe the King of Babylon. There is no Lucifer, no fallen angel, and this verse has nothing to do with the Satan. The versions that talk about Lucifer indeed changed the text of Isaiah 14:12.
It would help if you posted it. This is what it says in KJ. Satan is NOT the morning star. Jesus is! - Isaiah 14:12 12 How art thou fallen from heaven, O Lucifer, son of the morning ! how art thou cut down to the ground, which didst weaken the nations! - Revelation 2:28 And I will give him the morning star. - Revelation 22:16 I Jesus have sent mine angel to testify unto you these things in the churches. I am the root and the offspring of David, and the bright and morning star.