Vaani is an 18-layer acoustic pipeline for IELTS/TOEFL Speaking — Praat formants, peer-reviewed rhythm, syntax-tree grammar → Contrastive Interference Function against 8 Indian-L1 attractors (Bengali + Hindi on Svarah; six on published phonetics). No LLM. No GPU. Same audio = same band. Every L1 callout needs two-piece evidence: acoustic detection AND catalogue match — otherwise unlabelled, never pinned to an L1. Vaani tells you what it measured, how confident, and what it couldn't.