I don't believe the word of God is bound by words or language so to say the KJV doesn't match the original word or what we think the original word meant hs no bearing on accuracy. Just like "the gospel" vs "good news", both mean exactly the same thing but to say "good news" obscures the fact that the gospel was preached to the old testament saints.I don't think knowledge of original languages would change anything.
He is not talking about accuracy of translation. He is talking about an inspired English text; in which even deviation from the original language mss used are inspired. Both King James' instructions to the translators and the translator's preface argue against this belief; but he believes it anyway.
Hebrews 4 King James Version (KJV)
4 Let us therefore fear, lest, a promise being left us of entering into his rest, any of you should seem to come short of it.
2 For unto us was the gospel preached, as well as unto them: but the word preached did not profit them, not being mixed with faith in them that heard it.