Today I'd like to approach the language question from another angle. Because not only does the English language change, but ancient languages change, too.
Since the King James Version was first translated, whole libraries of ancient texts have been unearthed from the time of the Bible. In the past 100 years, "new" ancient languages have even been discovered! These texts are written in Akkadian, Ugaritic, Hittite, Phoenician, and other languages closely related to Hebrew. They are helping scholars understand the Bible better than ever before.
In the past, translators have often had to guess at the meanings of Hebrew words that occur only once or cultural concepts that seemed obscure. Sometimes they still do. But ironically, we understand the ancient world better now than ever before, thanks to these discoveries and the scholars who have devoted their lives to pouring over them. Hebrew dictionaries are getting better all the time. Now translators can compare with other texts and in some cases the meaning of a biblical term or concept becomes clear.
If you notice a significant change in a newer translation, there is a good possibility that this is why. Ancient copies of the Bible didn't come with a glossary attached. Translators have to work hard to understand the sense of a Hebrew, Aramaic, or Greek word and then search for a good way to say it in English.
Occasionally, a discovery will impact a passage that is known and loved by so many people that the translators are in a tough spot. Should they use what they now know of ancient languages to offer a better translation? Or will "changing" this verse make people suspicious of the new translation because it is different from what they know? Call this "pastoral concern" or call this "politics" or call this "good business." The fact is that if people won't buy it and read it, the best translation in the world is useless. The committee has had to make some tough calls, because sometimes some of the best-loved verses are most resistant to revision.
Take Psalm 23 for example. Though I grew up reading the NIV, I'm old enough to still have the KJV echoing in my head.
"Yea, though I walk through the valley of the shadow of death,The old NIV updated the English only slightly by removing "yea" and "thou." Hebrew has no special pronouns for deity, so why use them in English when we no longer talk this way?
I will fear no evil, for thou art with me . . ." (Psalm 23:4a, KJV)
"Even though I walk through the valley of the shadow of death,But the new NIV "tampered" with something much closer to the hearts of many:
I will fear no evil, for you are with me . . . " (Psalm 23:4a, NIV 1984)
"Even though I walk through the darkest valley,
I will fear no evil, for you are with me . . ." (Psalm 23:4a, NIV 2011)
What happened to "the valley of the shadow of death"?! That's the best part of the psalm!
If you look closely, you'll find that it's been moved to the footnotes, where it says, "Or the valley of the shadow of death." But the scholarship behind this shift isn't brand new. If you check the footnotes of the older NIV, you'll find that it says, "Or through the darkest valley." In other words, the translators have been aware of another way to translate this word since at least 1983. But perhaps they didn't feel we were ready for the change.
The Hebrew word behind this is צַלְמָוֶת (tsal-mavet). Can you find it in this picture of Psalm 23 from my Hebrew Bible? (hint: it's in the last line of Hebrew text, just above the number 2671.)
It's a compound word, and if you break it apart the two parts mean "shadow" and "death" respectively. But keep in mind that many compound words don't hold their meaning when you break them apart. Have you ever seen "butter" "fly"? Then you get my point.
In this case, the ancient Greek translation of the Hebrew Bible, known as the Septuagint, rendered the Hebrew צַלְמָוֶת as two words in Greek meaning "shadow" and "death." Perhaps their Hebrew was rusty and they didn't know this word. But now we do. According to The Hebrew and Aramaic Lexicon of the Old Testament צַלְמָוֶת means "gloom," or "an impenetrable darkness." They attribute the translation "shadow of death" to "folk etymology."
(To complicate matters, The Dictionary of Classical Hebrew still considers that the word could mean "shadow of death." In other words, scholars are still working on this one. And each translation committee will have to use their best judgment.)
What grieves me about the misinformation floating around cyberspace about the NIV is that it is often based on fear rather than solid study. The good scholarly work of those who updated the NIV is rejected because people who are not trained to evaluate a translation blow the whistle. Their good intentions (protecting the Word of God) inhibit the majority from having access to the best translation possible. Do us all a favor. Don't be that whistle blower. Do your homework.