Abstract: A system and method for indexing and searching textual archives using semantic units such as syllables and morphemes. In one aspect, a system for indexing a textual archive comprises an AHR (automatic handwriting recognition) system and/or OCR (optical character recognition) system for transcribing (decoding) textual input data (handwritten or typed text) into a string of semantic units (e.g., syllables or morphemes) using a statistical language model and vocabulary based on semantic units (such as syllables or morphemes). The string of semantic units that result from a decoding process are stored in a semantic unit database and indexed with pointers to the corresponding textual data in the textual archive. In another aspect, a system for searching a textual archive is provided, wherein a word (or words) to be searched is rendered into a string of semantic units (e.g., syllables or morphemes) depending on the application.