The Hebrew Scriptures themselves, though covering a wide range of subjects and employing an extensive vocabulary, by no means contain all the words or expressions of ancient Hebrew. The Siloam inscription and the Lachish ostraca, for example, contain certain word and grammatical constructions that do not appear in the Hebrew Scriptures, yet these constructions are clearly of Hebrew origin. Undoubtedly the ancient vocabulary of the Hebrew-speaking people contained many more “root” words, plus thousands of words derived from these, than are known today.

Aside from those portions of the Bible definitely known to be written in Aramaic, there are quite a number of words and expressions found in the Hebrew Scriptures for which the original “roots” are unknown. Lexicographers classify many of these as “loanwords,” claiming that Hebrew borrowed these from other Semitic tongues, such as Aramaic, Akkadian, or Arabic. This is speculation, however. As Edward Horowitz states: “But sometimes the borrowing is so ancient that scholars do not know which language did the borrowing and which was the original owner.” (How the Hebrew Language Grew, pp. 3, 5) It seems more probable that such questioned terms are genuinely Hebrew and are further evidence of the incompleteness of modern knowledge of the scope of the ancient language.

Among the evidences pointing to a rich vocabulary in ancient Hebrew are writings from the start of the Common Era. These include non-Biblical religious writings forming part of the Dead Sea Scrolls, and also the Mishnah, a body of rabbinic writings in Hebrew dealing with Jewish tradition. Writing in The Encyclopedia Americana (1956, Vol. XIV, p. 57a), Professor Meyer Waxman says: “Biblical Hebrew . . . does not exhaust the entire stock of words, as is proved by the Mishnah, which employs hundreds of Hebrew words not found in the Bible.” Of course, some of these could have been later additions or coined expressions, but doubtless many were part of the Hebrew vocabulary during the period of the writing of the Hebrew Scriptures.

Further reason for believing that the Hebrew of the Bible accurately represents the “one language” of pre-Babel times is the remarkable stability of the Hebrew language during the thousand-year period in which the Hebrew Scriptures were written. As The International Standard Bible Encyclopedia states: “One of the most remarkable facts connected with the Hebrew of the O[ld] T[estament] is that, although its literature covers a period of over a thousand years, the language (grammar and vocabulary) of the oldest parts differs little from that of the latest.”​—Edited by G. W. Bromiley, 1982, Vol. 2, p. 659.