A method performed in connection with an arrangement of nodes representable as a graph, and an inverted index containing a correlation among keywords and nodes such that at least some nodes containing a given keyword are indexed to that given keyword, involves receiving a word, searching the inverted index to determine whether the word is a keyword and, if the word is a keyword, jumping to a node identified in the inverted index as correlated to that keyword, otherwise, learning a meaning for the word based upon reaching a result node and applying at least one specified rule such that a new input containing the word can be received thereafter and the word from the new input will be treated according to the learned meaning.