The document discusses the classification of consonants according to their manner and place of articulation. It explains that consonants are produced by a constriction in the vocal tract and classified based on three dimensions: place of articulation, manner of articulation, and voicing. Place of articulation refers to where in the vocal tract the constriction occurs. Manner of articulation describes how narrow the constriction is and whether air flows through the nose. The document provides detailed descriptions of different manners of articulation including plosives, affricates, nasals, fricatives, lateral, and approximants. It also lists the place of articulation for various consonants and provides examples.