The Prātiçākhya Sūtra of the Rigveda is an extensive metrical work in three books, traditionally attributed to Çaunaka, the teacher of Āçvalāyana; it may, however, in its present form only be a production of the school of Çaunaka. This Prātiçākhya was later epitomised, with the addition of some supplementary matter, in a short treatise entitled Upalekha. The Taittirīya Prātiçākhya is particularly interesting owing to the various peculiar names of teachers occurring among the twenty which it mentions. The Vājasaneyi Prātiçākhya, in eight chapters, names Kātyāyana as its author, and mentions Çaunaka among other predecessors. The Atharva-veda Prātiçākhya, in four chapters, belonging to the school of the Çaunakas, is more grammatical than the other works of this class.
Metre, to which there are many scattered references in the Brāhmaṇas, is separately treated in a section of the Çānkhāyana Çrauta Sūtra (7, 27), in the last three sections (paṭalas) of the Rigveda Prātiçākhya, and especially in the Nidāna Sūtra, which belongs to the Sāmaveda. A part of the Chhandaḥ Sūtra of Pingala also deals with Vedic metres; but though it claims to be a Vedānga, it is in reality a late supplement, dealing chiefly with post-Vedic prosody, on which, indeed, it is the standard authority.
Finally, Kātyāyana’s two Anukramaṇīs or indices, mentioned below, each contains a section, varying but slightly from the other, on Vedic metres. These sections are, however, almost identical in matter with the sixteenth paṭala of the Rigveda Prātiçākhya, and may possibly be older than the corresponding passage in the Prātiçākhya, though the latter work as a whole is doubtless anterior to the Anukramaṇī.
The Padapāṭhas show that their authors had not only made investigations as to pronunciation and Sandhi, but already knew a good deal about the grammatical analysis of words; for they separate both the parts of compounds and the prefixes of verbs, as well as certain suffixes and terminations of nouns. They had doubtless already distinguished the four parts of speech (padajātāni), though these are first mentioned by Yāska as nāman, or “noun” (including sarva-nāman, “representing all nouns” or “pronouns”), ākhyāta, “predicate,” i.e. “verb”; upasarga, “supplement,” i.e. “preposition”; nipāta, “incidental addition,” i.e. “particle.” It is perhaps to the separation of these categories that the name for grammar, vyākaraṇa, originally referred, rather than to the analysis of words. Even the Brāhmaṇas bear evidence of linguistic investigations, for they mention various grammatical terms, such as “letter” (varṇa), “masculine” (vṛishan), “number” (vachana), “case-form” (vibhakti).Still more such references are to be found in the Āraṇyakas, the Upanishads, and the Sūtras. But the most important information we have of pre-Pāṇinean grammar is that found in Yāska’s work.
Grammatical studies must have been cultivated to a considerable extent before Yāska’s time, for he distinguishes a Northern and an Eastern school, besides mentioning nearly twenty predecessors, among whom Çākaṭāyana, Gārgya, and Çākalya are the most important. By the time of Yāska grammarians had learned to distinguish clearly between the stem and the formative elements of words; recognising the personal terminations and the tense affixes of the verb on the one hand, and primary (kṛit) or secondary (taddhita) nominal suffixes on the other. Yāska has an interesting discussion on the theory of Çākaṭāyana, which he himself follows, that nouns are derived from verbs. Gārgya and some other grammarians, he shows, admit this theory in a general way, but deny that it is applicable to all nouns. He criticises their objections, and finally dismisses them as untenable. On Çākaṭāyana’s theory of the verbal origin of nouns the whole system of Pāṇini is founded. The sūtra of that grammarian contains hundreds of rules dealing with Vedic forms; but these are of the nature of exceptions to the main body of his rules, which are meant to describe the Sanskrit language. His work almost entirely dominates the subsequent literature. Though belonging to the middle of the Sūtra period, it must be regarded as the definite starting-point of the post-Vedic age. Coming to be regarded as an infallible authority, Pāṇini superseded all his predecessors, whose works have consequently perished. Yāska alone survives, and that only because he was not directly a grammarian; for his work represents, and alone represents, the Vedānga “etymology.”
Yāska’s Nirukta is in reality a Vedic commentary, and is older by some centuries than any other exegetical work preserved in Sanskrit. Its bases are the Nighaṇṭus, collections of rare or obscure Vedic words, arranged for the use of teachers. Yāska had before him five such collections. The first three contain groups of synonyms, the fourth specially difficult words, and the fifth a classification of the Vedic gods. These Yāska explained for the most part in the twelve books of his commentary (to which two others were added later). In so doing he adduces as examples a large number of verses, chiefly from the Rigveda, which he interprets with many etymological remarks.
The first book is an introduction, dealing with the principles of grammar and exegesis. The second and third elucidate certain points in the synonymous nighaṇṭus; Books IV.–VI. comment on the fourth section, and VII.–XII. on the fifth. The Nirukta, besides being very important from the point of view of exegesis and grammar, is highly interesting as the earliest specimen of Sanskrit prose of the classical type, considerably earlier than Pāṇini himself. Yāska already uses essentially the same grammatical terminology as Pāṇini, employing, for instance, the same words for root (dhātu), primary, and secondary suffixes. But he must have lived a long time before Pāṇini; for a considerable number of important grammarians’ names are mentioned between them. Yāska must, therefore, go back to the fifth century, and undoubtedly belongs to the beginning of the Sūtra period.
One point of very great importance proved by the Nirukta is that the Rigveda had a very fixed form in Yāska’s time, and was essentially identical with our text. His deviations are very insignificant. Thus in one passage (X. 29. I) he reads vāyó as one word, against vā yó as two words in Çākalya’s Pada text. Yāska’s paraphrases show that he also occasionally differed from the Saṃhitā text, though the quotations themselves from the Rigveda have been corrected so as to agree absolutely with the traditional text. But these slight variations are probably due to mistakes in the Nirukta rather than to varieties of reading in the Rigveda. There are a few insignificant deviations of this kind even in Sāyaṇa, but they are always manifestly oversights on the part of the commentator.
To the Sūtras is attached a very extensive literature of Pariçishṭas or “supplements,” which seem to have existed in all the Vedic schools. They contain details on matters only touched upon in the Sūtras, or supplementary information about subjects not dealt with at all by them. Thus, there is the Āçvalāyana Gṛihya-pariçishṭa, in four chapters, connected with the Rigveda. The Gobhila saṃgraha-pariçishṭa is a compendium of Gṛihya practices in general, with a special leaning towards magical rites, which came to be attached to the Sāmaveda. Closely related to, and probably later than this work, is the Karma-pradīpa (“lamp of rites”), also variously called sāma-gṛihya- or chhāndogyagṛihya-pariçishṭa, chhandoga-pariçishṭa, Gobhila-smṛiti, attributed to the Kātyāyana of the White Yajurveda or to Gobhila. It deals with the same subjects, though independently, as the Gṛihya saṃgraha, with which it occasionally agrees in whole çlokas.
Of great importance for the understanding of the sacrificial ceremonial are the Prayogas (“Manuals”) and Paddhatis (“Guides”), of which a vast number exist in manuscript. These works represent both the Çrauta and the Gṛihya ritual according to the various schools. The Prayogas describe the course of each sacrifice and the functions of the different groups of priests, solely from the point of view of practical performance, while the Paddhatis rather follow the systematic accounts of the Sūtras and sketch their contents. There are also versified accounts of the ritual called Kārikās, which are directly attached to Sūtras or to Paddhatis. The oldest of them appears to be the Kārikā of Kumārila (c. 700 A.D.).