claim 1 further comprising the step of identifying mapped nodes in said tree to determine which nodes form a path between a leaf node to the root node of said tree by soliciting and receiving additional recognizable keywords iteratively to obtain a plurality of input tokens.
3. An apparatus for understanding natural language utterances within a well-defined language comprised of a set of predetermined, understandable keywords within a predetermined dictionary of such understandable keywords, said understandable keywords being representable by a tree graph formed by nodes that include a root node, leaf nodes, and intermediate nodes between said root and leaf nodes, each leaf node and intermediate node representing one of more keywords in said predetermined dictionary of understandable keywords, syntactical relationships between recognizable keywords in said language being specified and representable by paths, formed by the edges in said tree graph linking said leaf nodes and said intermediate nodes to said root node in a predetermined order, comprising:
a) input means for obtaining at least one input token representing an utterance from a user and determining if said at least one input token represents a recognizable keyword and mapping the occurrence of said recognizable keyword to a node in said tree, forming thereby mapped nodes in said tree;
b) determination means for identifying mapped nodes in said tree to determine which nodes form a path between a leaf node to the root node of said tree;
c) identification means for identifying recognizable keywords of said language that are represented by said leaf node of to be an understood utterance of said user; and
d) means for identifying mapped nodes in said tree to determine which nodes form a path between a leaf node to the root node of said tree by soliciting and receiving additional recognizable keywords and testing mapped nodes according to a predetermined probability that mapped nodes correspond to a user's utterance.
4. The apparatus of claim 3 further including: means for identifying a complete path between a leaf node to the root node of said tree.
5. The apparatus of claim 3 further including: means for identifying mapped nodes in said tree to determine which nodes form a path between a leaf node to the root node of said tree by soliciting and receiving additional recognizable keywords iteratively for a plurality of input tokens.
6. The apparatus of claim 3 where said input means for obtaining at least one input token, said means for identifying mapped nodes, and said means for identifying recognizable keywords is a computer.
7. The apparatus of claim 3 where said input means for obtaining at least one input token is a keyboard.
8. The apparatus of claim 3 where said input means for obtaining at least one input token is a pointing device.
9. The apparatus of claim 3 where said input means for obtaining at least one input token is a handwriting recognition device.
10. The apparatus of claim 3 where said input means for obtaining at least one input token is facsimile machines.
11. The apparatus of claim 3 where said input means for obtaining at least one input token is an optical character recognition device.
12. The apparatus of claim 3 where said input means for obtaining at least one input token is output from a computer program.
This invention relates to processing and understanding natural language input from a device such as but not limited to a speech recognition system.
Speech or voice recognition systems are well known and are becoming more widely used in computer-based user interface systems, such as voice-activated dialing and telephone systems, and speech-based handicap aids, etc. Such systems might someday replace the now-ubiquitous menu driven telephone answering systems by which a telephone call is routed to a particular person or department for example, by a list of choices presented to a caller via recorded message.
Speech recognition systems that are in use today typically use statistical models to store representations of words and try to map a sp