1. The Three Stage Theory of the History of Ancient Hebrew
Using the sources available to them, by the end of the nineteenth century scholars had been able to construct an elegant theory of the history of Hebrew in the ancient period. The main evidence that scholars used was the Hebrew Bible. More specifically, for them, as is still the case with language scholars today, "the Bible" meant the traditional Masoretic Text of the books of the Tanach, the one readily available to everyone who has a Hebrew Bible. The Bible was, however, not the only evidence that scholars in the nineteenth century had available to them for ancient Hebrew. They were also aware that early rabbinic works like the Mishnah used a noticeably different sort of Hebrew, which is often called "Mishnaic Hebrew." Third, these early scholars were aware that from the late biblical period on, Hebrew competed in the Jewish homeland with the Aramaic language. Various forms of evidence in rabbinic sources or in other sources like the New Testament Gospels (see, for example Jesus' quoted use of Aramaic in the Greek text of Mark 5:41 and elsewhere) indicated that Hebrew's battle against Aramaic in the Jewish homeland was often a losing one.
According to this scholarly theory, there were three main periods in the history of ancient Hebrew. First, before the exile to Babylon in the sixth century BCE was the "Golden Age" of Hebrew literature. Early works of literature such as the story of King David in the Book of Samuel, or the early parts of the Mosaic Pentateuch were written in pure Classical Hebrew. After the Babylonian exile, however, according to this theory, Hebrew lost ground to Aramaic. Factors such as the rise in non-native speakers of Hebrew, and the breaking of the continuity of the pre-exilic educational system meant that Hebrew declined. Evidence for this was found in the Bible. The books of Esther, Daniel, Ezra, Nehemiah and Chronicles, by their contents, are among the books that must have been composed after the return from exile. It happens that each of these books shares a peculiar style of Hebrew, which sets them clearly apart from works of the Golden Age, such as Samuel. The main characteristic of this style is actually simply a greater openness to linguistic variety than is typical of the language of a book like Samuel.
However, since some of the additional linguistic features which these books like to use are found in Aramaic or "Mishnaic Hebrew", and since some passages in these books seem rather difficult to comprehend (try Daniel chapter eight, for example), these books were taken as a symptom that Hebrew in the post-exilic period was in a state of decline. Scholars therefore called this second period the "Silver Age" of Hebrew literature. The idea of decline was also used to explain the third era of the history of ancient Hebrew. Under the influence of Aramaic and other factors, Hebrew continued to decline in the post-exilic period, according to this theory, until by the CE period the Mishnaic Hebrew of the Rabbis represents a thoroughly unclassical form of Hebrew, perhaps an Aramaised form of Hebrew.
The three-stage linear model of the development of ancient Hebrew was a reasonable and logical deduction from the evidence as it was available and understood at that time. The three-stage model, of a pre-exilic Golden Age down to about the sixth century BCE, a post-exilic Silver Age, and a post-biblical, post-classical age, was furthermore of great use to scholars when discussing biblical books. Since Hebrew was understood to have developed in a linear fashion, away from early, pure, classical Hebrew under Aramaic influence towards the form of language found in the Mishnah, it was possible to argue where on that linear development works of uncertain date were to be put. Note the following paragraph on the language of Qoheleth (or Ecclesiastes) from the authoritative Encyclopaedia Biblica, published in 1899, which is a good illustration of the results of nineteenth century scholarship:
[T]he language . …