The Brahmi family divides broadly along two lines of descent, a northern branch that produced Siddham, Devanagari and most of the scripts of North India, Nepal and Tibet, and a southern branch that produced the scripts of Sri Lanka and much of South India, though centuries of contact, trade and religious exchange mean the boundary between the two is porous rather than absolute. Buddhism and Hinduism alike carried scripts from this family well beyond India's own borders as their texts spread, which is why Southeast Asian scripts used for Thai, Burmese, Khmer and other languages, though not all separately catalogued in this atlas, also trace their ultimate ancestry to the same Brahmi root.
Sacred use runs through the whole family rather than any one member: Devanagari carries the bulk of surviving Sanskrit religious literature, Siddham carried Buddhist mantras and sutras into East Asia where it is still used ceremonially in some Japanese Shingon Buddhist practice, and Gurmukhi was specifically developed to give Sikh scripture a script of its own distinct from the Perso Arabic and Devanagari scripts already in regional use. The family's unity is historical and structural, a shared abugida logic and a shared ancestor, rather than religious: its descendant scripts serve Hindu, Buddhist, Sikh, Jain and secular writing alike across the subcontinent and beyond.