The first/foremost condition for teaching-learning language at the primary level is –

An environment rich in language input and communication (निवेश-समृद्ध संप्रेषण का वातावरण) is the foremost requirement, aligning with Krashen's input hypothesis. Children acquire language best when surrounded by meaningful, comprehensible language use. A simple textbook, literature, or decorated classroom are supplementary, not foundational.