A vachana is short, unrhymed, spoken in the plainest possible Kannada, and addressed straight at Siva as if he were standing in the room. That directness was the point. Twelfth century Karnataka already had an elaborate, Sanskrit trained literary culture, ornate and formal, and the vachana poets walked away from nearly all of it, choosing instead a form close enough to ordinary speech that anyone could have composed one and, in the tradition's own telling, many did.
Speaking of Siva collects the work of four of them, and reading them side by side is the fastest way to see that Lingayatism was never a single poetic voice reciting a fixed doctrine. Basavanna, the twelfth century social reformer credited with founding the tradition, writes with the blunt moral urgency of someone arguing a case. Mahadeviyakka, a woman who reportedly renounced marriage and possessions to wander in devotion to Siva alone, writes with an intimacy bordering on the erotic, addressing him as a lover. Allama Prabhu favors riddle and paradox, doctrine turned into puzzle. Devara Dasimayya, generally read as the earliest of the four, writes in a more settled, aphoristic register.
What holds these four together is not a shared style but a shared refusal: no priest, no temple ritual, no caste distinction standing between the devotee and God. Each poet reaches that position by a different road, and the collection's real achievement is letting a reader hear four distinct people arrive at broadly the same freedom from four different directions.