None of the Bible is "very early" in its "present form." That is, linguistic evidence points to a continual updating of the text as the language evolved, with the final textual form being reached after the return from Babylonian exile.

For example, The song of Deborah and Barak in Judges 5 is cast in an older form of the language than the surrounding prose text, much the same as if a modern history text included by way of illustration an Elizabethan ballad.

That said, the integrity of the text was helped by the writing being, at least in the beginning, thoroughly consonantal, with the vowels being added, in various methodologies, in later centuries. And the way the consonants were written allowed for some flexibility between full stops and affricatives and spirants.

For example, the difference in writing between a "p" and an "f" is a small dot in the center of the letter. And b/v. d/dh, g/gh, etc., are all distinguished in the same way.

Thus rather substantial changes in the pronunciation would have relatively little effect on the written language. So even though the "present form" is different from the "very early" form, the differences are not great enough to cause great difficulty determining the probable original form of most words. And the vocabulary seems to have been remarkably stable up until NT times.