A natural language processing apparatus configured to analyze a plurality of natural language elements, includes processing configured to input for each natural language element, multiple sign language images for a certain natural language together with the respective natural language, extract multiple feature points of a first sign language motion from the input sign language images and analyze a common point or a differing point between the first sign language motion and a second sign language motion, for each of the extracted feature points, deduce semantic content of the natural language element from the analyzed common point or the differing point, and a storage configured to store in association with the natural language element, information regarding the deduced semantic content. The processing circuitry analyzes the natural language using an artificial intelligence algorithm.