Jain Prakrit is a term loosely used for the language of the Jain canon.

The books of Jainism were written in the popular dialects as opposed to Sanskrit, which was the language of the dominant Vedantic canon, and therefore encompass a number of dialects. Chief among these is Ardha Magadhi, which due to its extensive use has also come to be identified as the definitive form of Prakrit. Other dialects include versions of Maharashtri and Sauraseni.

The "Aabhidhan Rajendra Kosh" written by Acharya Rajendrasuri, is the only available Jain encyclopedia for understanding the Jain Prakrit, Sanskrit, Ardha-Magadhi and other Jain languages words.

Pali and Ardha-Magadhi

The most archaic of the Middle Indo-Aryan languages are the inscriptional Aśokan Prakrit on the one hand and Pāli and Ardhamāgadhī on the other, both literary languages.

The Indo-Aryan languages are commonly assigned to three major groups - Old, Middle and New Indo-Aryan -, a linguistic and not strictly chronological classification as the MIA languages ar not younger than ('Classical') Sanskrit. And a number of their morphophonological and lexical features betray the fact that they are not direct continuations of Ṛgvedic Sanskrit, the main base of 'Classical' Sanskrit; rather they descend from dialects which, despite many similarities, were different from Ṛgvedic and in some regards even more archaic.

MIA languages, though individually distinct, share features of phonology and morphology which characterize them as parallel descendants of Old Indo-Aryan. Various sound changes are typical of the MIA phonology:

(1) The vocalic liquids 'ṛ' and 'ḷ' are replaced by 'a', 'i' or 'u';
(2) the diptongs 'ai' and 'au' are monophthongized to 'e' and 'o';
(3) long vowels before two or more consonants are shortened;
(4) the three sibilants of OIA are reduced to one, either 'ś' or 's';
(5) the often complex consonant clusters of OIA are reduced to more readily pronounceable forms, either by assimilation or by splitting;
(6) single intervocalic stops are progressively weakened;
(7) dentals are palatalized by a following '-y-';
(8) all final consonants except '-ṃ' are dropped unless they are retained in 'sandhi' junctions.

The most conspicuous features of the morphological system of these languages are: loss of the dual; thematicization of consonantal stems; merger of the f. 'i-/u-' and 'ī-/ū-' in one 'ī-/ū-' inflexion, elimination of the dative, whose functions are taken over by the genitive, simultaneous use of different case-endings in one paradigm; employment of 'mahyaṃ' and 'tubhyaṃ' as genitives and 'me' and 'te' as instrumentals; gradual disappearance of the middle voice; coexistence of historical and new verbal forms based on the present stem; and use of active endings for the passive. In the vocabulary, the MIA languages are mostly dependent on Old Indo-Aryan, with addition of a few so-called 'deśī' words of (often) uncertain origin.

There are many remarkable analogies between Pali and Ardhamagadhi (Half Magadhi), an old form of Magadhi preserved in ancient Jain texts. Ardhamagadhi differs from the eastern Prakrit of Ashokan inscriptions on similar points as Pali. For example, Ardhamagadhi too does not change r
into l, and in the noun inflexion it shows the ending -o instead of the eastern Prakritic -e at least in many metrical places. This similarity is not accidental, since Mahavira, the 24th Tirthankara of Jainism preached in the same area (Magadha) as Buddha Gotama.

Dhammapada verse 103:

103. Yo sahassaṃ sahassena, saṅgāme mānuse jine;

Ekañca jeyyamattānaṃ, sa ve saṅgāmajuttamo.

Greater in battle than the man who would conquer a thousand-thousand men,

is he who would conquer just one — himself.

Jain Samana sutta 125:

Jo sahassam sahassanam, samgame dujjae jine.

Egam jinejja appanam, esa se paramo jao. (125)

One may conquer thousands and thousands of enemies in an invincible battle;

but the supreme victory consists in conquest over one's self.