Algorithms for speech indexing in microsoft recite

Microsoft Recite is a mobile application to store and retrieve spoken notes. Recite stores and matches n-grams of pattern class identifiers that are designed to be language neutral and handle a large number of out of vocabulary phrases. The query algorithm expects noise and fragmented matches and compensates for them with a heuristic ranking scheme. This contribution describes a class of indexing algorithms for Recite that allows for high retrieval accuracy while meeting the constraints of low computational complexity and memory footprint of embedded platforms. The results demonstrate that a particular indexing scheme within this class can be selected to optimize the trade-off between retrieval accuracy and insertion/query complexity.