Ratha patha is one of the eight modes of recitation of Veda (called vikrti pathas), intended to preserve the textual purity of the words and accent of the Veda.
While samhita patha or karma patha is the recital of the hymns as they are, pada-patha is the recitation of the hymns with each word (pada) recited separately but sequentially. Vedic texts being handed down from teacher to pupil by word of mouth, it was realized that there was always a possibility of a letter being missed or the accent going wrong. Since pristine purity was essential to derive the full benefit of recitation of the hymns during prayers and rituals, eight modes of recitation of the texts were enunciated by the transfer or repetition of the words, which would enable the correlation and identification of the pure text, if ever needed.
These modes were Jata, Mala, Sikha, Rekha, Dhvaja, Danda, Ratha and Ghana, all of which were practiced by Vedic scholars all over the land. While ghana-patha is popular in South India, ratha-patha has been assiduously practiced in Kerala by the Namboothiri Brahmins.
The ratha patha order of words is as follows – if a,b,c,d are the words, the Ratha recitation would be: aba/abcda/abcdcba and abcdcdcba.
The recitation of ratha-patha by the Namboothiri Brahmins of Kerala retains the originally high udatta syllable at a high pitch (uccaih udattah) as ordained by the Sanskrit grammarian Panini. This, however, is not followed in other parts of India. It would seem that the Nampoothiri recitation is a unique survival of the old form of the recitation of ratha-patha.