A processor based system includes a parser, configured for identifying whether an input word received from a user is a new command word relative to a character-based command parse tree, and a tree management process configured for managing the character-based command parse tree. The character-based command parse tree includes multiple element levels for respective character positions for each known command word, and at least one character element at each level. Each character element specifies at least one corresponding character component and a corresponding at least one index value. The parser determines whether the input word is a new command word based on whether the characters of the input word match successive elements, with the last character matching an end node, within the character-based parse tree; if the parser determines that the input word is a new command word, the tree management process performs update operations to accommodate the new command word, including updating the character-based command parse tree with the new command word.