Old Novgorod dialect
Old Novgorod dialect (Russian: древненовгородский диалект, dryevnyenovgorodsky dialekt; also translated as Old Novgorodian or Ancient Novgorod dialect) is a term introduced by Andrey Zaliznyak to describe the astonishingly diverse linguistic features of the Old East Slavic birch bark writings ("berestyanaya gramota") from the 11th to 15th centuries excavated in Novgorod and its surroundings. The first birch bark letter was found on July 26, 1951 by Nina Fedorovna Akulova, and at least 1025 have been unearthed thereafter—923 in Novgorod alone. Today, the study of Novgorodian birch bark letters is an established scholarly field in Russian historical linguistics, with far-ranging historical as well as archaeological implications for the study of the Russian Middle Ages.
Linguistic features 
The short birch-bark texts are written in a peculiar Slavic vernacular, reflecting living speech, and almost entirely free of the heavy Church Slavonic influence seen in the literary language of the period. Some of the observed linguistic features are not found in any other Slavic dialect, representing important Proto-Slavic archaisms.
Zaliznyak differentiates amongst Old Novgorod features that were already known before the discovery of birch bark letters, and those that have been ascertained after their study during the last few decades. Features previously known were:
- secondary pleophony, i. e. мълъвити as opposed to мълвити
- retention of /x/ in the root of the word "весь", i. e. вьхо
- lack of the Slavic second palatalization in root-final position, i. e. рукѣ, моги
- the change vl’ > l’, i. e. Яколь, Яковлев
- nominative singular masculine of o-stems -e, i. e. Иване, посаднике, хлѣбе
- genitive singular of а-stems in -ě i. e. бес кунѣ
- nominative-accusative plural of а-stems in -ě, i. e. кобылѣ, сиротѣ
Features of the Old Novgorod dialect ascertained by the philological study in the last decades are:
- lack of the second palatalization in root-initial position, i. e. кѣл-, хѣр-
- a particular reflex of *CъRC clusters, i. e. млъви versus мълви
- a particular reflex of *CоRC clusters, i. e. погродье versus погородие
- the change ml’ > n’, i. e. емлючи > енючи
- no merger of nominative and accusative singular of masculines regardless of animacy, i. e. N sg. погосте : A sg. на погостъ
- Proto-Slavic *kv, *gv clusters were retained (like in West Slavic languages) instead of being transformed to cv, zv before front vowels like in other East Slavic dialects
Often the orthography is domestic (as opposed to bookish), using ъ and о on the one hand and ь and е on the other synonymously (about 50% of birch-bark documents from the mid-12th to the late 14th century).
Implications of Old Novgorod findings 
According to Zaliznyak, the Old Novgorod linguistic features, instead of being merely isolated deviations, represent a bundle of peculiar isoglosses. The deviations are more abundant in older birch bark letters than in the younger ones, and this development indicates, contrary to what is expected, that the development was convergent rather than divergent, with regard to other northern East Slavic dialects.
Therefore, according to Zaliznyak, the discovery of Old Novgorod dialect makes it possible to conclude that earlier conception of East Slavic as a relatively homogeneous linguistic unity has been rendered obsolete by a view of East Slavic as an area of much greater dialectal diversity. Zaliznyak therefore divides East Slavic area into two dialectal groupings: Proto-Novgorodian-Pskovian on one side, singled out chiefly on the basis of two features of the lack of second palatalization of velars and the ending -e in nominative singular of masculine o-stems, and all the remaining East Slavic dialects on the other side.
(between end of 11th century and 1110s; excavated 1954)
Original text (with added word division):
грамота : ѡтъ жизномира : къ микѹле : кѹпилъ еси : робѹ : плъскове : а ныне мѧ : въ томъ : ѧла кънѧгыни : а ныне сѧ дрѹжина : по мя порѹчила : а ныне ка : посъли къ томѹ : моужеви : грамотѹ : е ли ѹ него роба : а се ти хочѹ : коне кѹпивъ : и кънѧжъ мѹжъ въсадивъ : та на съводы : а ты атче еси не възялъ кѹнъ : техъ : а не емли : ничъто же ѹ него :
Translation [with explanations in square brackets]:
Letter from Zhiznomir to Mikula: You have bought a female slave in Pskov. And now the princess has arrested me for it. [Obviously she has recognized the slave as having been stolen from her, and Zhiznomir is somehow connected with the affair, maybe as Mikula's family member or business partner.] But now druzhina has guaranteed for me. And now send a letter to that man [whom you have bought the slave from] and ask him whether he has another female slave. [This other slave would have to be given to the princess for the time the stolen slave would be needed as "corpus delicti" in a lawsuit to find out who the thief was.] And I want to buy a horse and have the magistrate (the "prince's man") sit on it and initiate a svod [the legal procedure to trace a whole buying chain back to the original seller and ultimately the thief]. And if you have not taken the money, do not take anything from him [i.e. the slave-trader, because otherwise the whole plan might leak out].
(1340s to 1380s; excavated 1972)
Original text (with added word division):
поколоно ѿ гаврили ѿ посени ко зати моемѹ ко горигори жи кѹмѹ ко сестори моеи ко ѹлите чо би есте поихали во городо ко радости моеи а нашего солова не ѡставили да бого вамо радосте ми вашего солова вохи не ѡсотавимо
Greeting from Gavrila Posenya to my brother-in-law, godfather Grigory and my sister Ulita. Would you not like to give me the pleasure of riding into the city, not leaving our word? God give you happiness. We all do not leave your word.
- I.e. the progressive palatalization did not take place; cf. vьx- "all" as opposed to modern Russian vs-
- E.g. Proto-slavic *rěka "river" was in dative singular *rěk-ě which was not reflected as **rěcě in Old Novgorod dialect but has been retained as rěkě.
- Instead of -ъ found in all the other Slavic dialects and reconstructed for Late Proto-Slavic, and that has been subsequently lost in a weak word-final position,; e.g. Old Novgorod dialect brate "brother" : modern Russian brat.
- Cf. also kьrky "church" which has remained kьrky : modern Russian cerkov.
- E.g. květ- "flower" : modern Russian cvet, gvězda "star" : modern Russian zvezda.
- Novgorod birch-bark letter no. 109
- Novgorod birch-bark letter no. 497
- Yanin, Valentin Lavrentyevich. Ja poslal tebe berestu... ("I've Sent a Birch Bark to You...") 3rd ed., with an afterword by A.A. Zaliznyak. Moscow 1998.
- Zaliznyak, Andrey Anatolyevich (2004). Древненовгородский диалект (in Russian). Moscow: Языки славянской культуры. ISBN 5-94457-165-9.