Automatic Language Growth (ALG) is a strict comprehensible-input approach, not another name for comprehensible input itself. It aims to develop natural language ability by delaying speaking and avoiding conscious analysis. Linguist J. Marvin Brown originally developed ALG for learners of Thai.
The approach focuses exclusively on comprehensible input and discourages activities such as grammar explanations, dictionary use, and early speaking. In ALG, comprehensible input is treated as the means by which language is acquired.
ALG became best known through classrooms where two native speakers interacted naturally using stories, demonstrations, jokes, props, and gestures. Learners listened, watched, and followed what was happening without being required to speak.