The introduction section of Sri. K. Parameswara Aithal’s book “Veda-Lakṣaṇa Vedic Ancillary Literature: A Descriptive Bibliography” (ISBN: 81-208-1120-8) gives an excellent overview of the Lakṣaṇa texts. Below are a few excerpts from the section:
Vedic ancillary texts, known as “lakṣaṇa granthas” define the characteristics and describe the special features of Vedic texts, they are generally termed “Veda-lakṣaṇa”. These texts are of ancillary nature and generally classified under Vedāṅga, though only a few of them belong to the proper Vedāṅga known as śikṣā-s. They include prātiśākhya-s, anukramaṇi-s, works on accentuation (svara), and on different forms of modified recitation (vikRti), and various kinds of indexes. It is generally not realized that these texts contain an abundance of valuable material for Vedic text-critical studies.
It is well known that most Vedic texts have been transmitted orally – from teacher to pupil – from early times to the present day. In spite of the fact that innumerable manuscripts of these sacred texts have existed for centuries and that printed books are available since the middle of the last century, only the oral tradition is recognized as authentic and authoritative. During Vedic rituals printed books, manuscripts or written notes are not allowed to be used. Even when one is reciting for ritual purposes, tradition generally does not permit the use of written material. This would divert the attention from the ritual act. Usually entire texts are learnt by heart before they are recited for ritual application.
For the purpose of easy learning and memorization as well as preservation of the sacred texts, tradition has evolved some peculiar but very useful devices which have been applied from time immemorial, and even now practiced in the traditional system of education. These devices help the students to learn and memorize entire texts – even large texts like the Rigveda – with utmost accuracy. This methodological and didactic aspect of Vedic and ritual text tradition has not yet been thoroughly and systematically investigated in modern Vedic scholarship.
Although traditional pandits do not use any written material during the actual recitation, there exist a large number of important texts which are used as external aid to instruction. A few of them, such as prātiśākhya-s and śikṣā-s are well known.
Veda-lakṣaṇa works can broadly be classified, on the basis of their essential features, into four categories:
- Works on Vedic phonetics, phonology, and some elements of Vedic grammar. Examples are prātiśākhya-s and the śikṣā-s, which deal with such topics as the alphabet (varṇa-samāmnāya), organs of articulation, etc. (sthāna, karaṇa, prayatna), correct pronunciation (uccāraṇa), euphonic combination (sandhi), proper accentuation (svara), etc.
- anukramaṇī-s – like the sarvānumramaṇī, bRhaddevatā (indices of the Seers, Dieties and metres), etc. To this category belongs also a large number of texts known as baiṭh-s, which deal with the same topic as the anukramaṇī-s but are composed in a code language and contain their own paribhāṣā-s and explanatory remarks. Some of these texts also make use of the kaṭapayādi system.
- Works containing lists of words, sometimes alphabetically arranged, words having peculiar characteristics in the Vedic texts, e.g., the cāturjñāna, the saptasaṅkhyā, and the saptalakṣaṇa, this last one comprising seven short tracts with the titles 1) aniṅgya 2) avarṇi, 3) āvarṇi, 4) tapara, 5) napara, 6) vilaṅghya and 7) samāna sandhi.
- Works mainly dealing with the modified forms of recitation. Some of them instruct in the formation of only one mode of recitation, like the upalekha-sūtra on the krama-pāṭha or the jaṭā-paṭala on the jaṭā-pāṭha. But others, like the aṣṭa-vikRti-kārikā, or the vikRti-vallī describe eight varieties of recitation.