Svadhyaya began as the most concrete of duties. In the Vedic schools, sva-adhyaya was one's own recitation: the daily repetition, aloud and from memory, of the portion of scripture a student had received from his teacher. The stakes were absolute, because the Veda was not written. For well over a millennium the entire corpus, tens of thousands of verses with their pitch accents intact, lived nowhere except in trained memories, and svadhyaya was the maintenance schedule of that living library. The schools built astonishing machinery around it: the pada recitation that isolates each word, the krama that chains word pairs, and the braided patterns, jata and ghana, that weave the text forward and backward so that any corruption in one pattern is caught by another. The result is a transmission so accurate that when manuscripts and printed editions finally appeared, recitations separated by a thousand miles agreed to the syllable. The lawbooks rank svadhyaya among the five daily obligations of the twice-born, calling it the sacrifice to Brahman, offered not in fire but in speech.
When Patanjali lists svadhyaya as the fourth niyama, this whole apparatus stands behind the word: study, in the Yoga Sutras, is not private reading but the disciplined, repeated, embodied keeping of a text until the text keeps you. The promised fruit at sutra 2.44, communion with one's chosen deity, assumes exactly that intimacy: what is recited daily for a lifetime is no longer information.