Mishnaic Hebrew is one of the few of the Hebrew dialects found in the Talmud, except for direct quotations from the Hebrew Bible. The dialects can be further sub-divided into Mishnaic Hebrew proper (also called Tannaitic Hebrew, Early Rabbinic Hebrew, or Mishnaic Hebrew I), which was a spoken language, and Amoraic Hebrew (also called Late Rabbinic Hebrew or Mishnaic Hebrew II), which was a literary language only.
The Mishnaic Hebrew language or Early Rabbinic Hebrew language is one of the direct ancient descendant of Biblical Hebrew as preserved by the Jews after the Babylonian captivity, and definitively recorded by Jewish sages in writing the Mishnah and other contemporary documents. It was not used by the Samaritans, who preserved their own dialect, Samaritan Hebrew.
A transitional form of the language occurs in the other works of Tannaitic literature dating from the century beginning with the completion of the Mishnah. These include the halachic Midrashim (Sifra, Sifre, Mechilta etc.) and the expanded collection of Mishnah-related material known as the Tosefta (תוספתא). The Talmud contains excerpts from these works, as well as further Tannaitic material not attested elsewhere; the generic term for these passages is Baraitot. The dialect of all these works is very similar to Mishnaic Hebrew.
Mishnaic Hebrew is found primarily from the 1st to the 4th centuries of the Common Era, corresponding to the Roman period after the destruction of the Temple in Jerusalem. Also called Tannaitic Hebrew or Early Rabbinic Hebrew, the dialect is represented by the bulk of the Mishnah (משנה, published around 200) and the Tosefta within the Talmud, and by some of the Dead Sea Scrolls, notably the Copper Scroll, and the Bar Kokhba Letters. Dead Sea Scrolls Archaeologist Yigael Yadin mentions that 3 Bar Kokhba documents he and his team found at Nahal Hever are written in Mishnaic Hebrew. But Yadin mentions that it was Bar Kokhba who revived Hebrew language and made Hebrew the official language of the state during Bar Kokhba revolt (132-135 AD). Yigael Yadin also noticed the shift from Aramaic to Hebrew during the time of Bar Kokhba revolt—in his book Bar Kokhba: The Rediscovery of the Legendary Hero of the Last Jewish Revolt Against Imperial Rome, Yadin notes, "It is interesting that the earlier documents are written in Aramaic while the later ones are in Hebrew. Possibly the change was made by a special decree of Bar-Kokhba who wanted to restore Hebrew as the official language of the state" (page 181). In Book "A Roadmap to the Heavens: An Anthropological Study of Hegemony among Priests, Sages, and Laymen (Judaism and Jewish Life)" by Sigalit Ben-Zion (Page 155), Yadin remarked: "it seems that this change came as a result of the order that was given by Bar Kokhba, who wanted to revive the Hebrew language and make it the official language of the state."
Within a century after the publication of the Mishnah, Mishnaic Hebrew began to fall into disuse as a spoken language. The Babylonian Gemara (גמרא, circa 500), as well as the earlier so-called Jerusalem Talmud published between 350 and 400, generally comment on the Mishnah and Baraitot in Aramaic. Nevertheless, Hebrew survived as a liturgical and literary language in the form of later Amoraic Hebrew, which sometimes occurs in the Gemara text.
Mishnaic Hebrew developed under the profound influence of spoken Aramaic in all spheres of language, including phonology, morphology, syntax and vocabulary.
Many of the characteristic features of Mishnaic Hebrew pronunciation may well have been found already in the period of Late Biblical Hebrew. A notable characteristic distinguishing it from Biblical Hebrew of the classical period is the spirantization of post-vocalic stops (b, g, d, p, t, k), which it has in common with Aramaic.
A new characteristic is that final /m/ is often replaced with final /n/ in the Mishna (see Bava Kama 1:4, "מועדין") but only in agreement morphemes. Perhaps the final nasal consonant in the morphemes was not pronounced, and the vowel previous to it was nasalized. Alternatively, the agreement morphemes may have changed under the influence of Aramaic.
Also, some surviving manuscripts of the Mishna confuse guttural consonants, especially (א) (a glottal stop) and 'ayin (ע) (a voiced pharyngeal fricative). That could be a sign that they were pronounced the same in Mishnaic Hebrew.
Mishnaic Hebrew displays various changes from Biblical Hebrew, some appear alreadying in the Hebrew of the Dead Sea Scrolls. Some, but not all, are retained in Modern Hebrew.
For the expression of possession, Mishnaic Hebrew mostly replaces the Biblical Hebrew status constructus with analytic constructions involving של 'of'.
Missing in Mishnaic Hebrew is the waw-consecutive.
The past is expressed by using the same form as in Modern Hebrew. For example, (Pirkei Avoth 1:1): "משה קיבל תורה מסיני". ("Moses received the Torah from Sinai".)
Continuous past is expressed using the present tense of to be unlike Biblical but like Modern Hebrew. For example, (Pirkei Avoth 1:2): "הוא היה אומר" ("He often said".)
Present is expressed using the same form as in Modern Hebrew, by using the participle (בינוני). For example, (Pirkei Avoth 1:2): "על שלושה דברים העולם עומד". ("The world is sustained by three things", lit. "On three things the world stands")
Future can be expressed using עתיד + infinitive. For example, (Pirkei Avoth 3:1): "ולפני מי אתה עתיד ליתן דין וחשבון". However, unlike Modern Hebrew but like contemporary Aramaic, the present active participle can also express the future. It mostly replaces the imperfect (prefixed) form in that function.
The imperfect (prefixed) form, which is used for the future in modern Hebrew, expresses an imperative (order), volition or similar meanings in Mishnaic Hebrew. For example, (Pirkei Avoth 1:3): "הוא היה אומר, אל תהיו כעבדים המשמשין את הרב" ("He would say, don't be like slaves serving the master...", lit. "...you will not be..."). In a sense, one could say that the form pertains to the future in Mishnaic Hebrew as well, but it invariably has a modal (imperative, volitional, etc.) aspect in the main clause.