# US 11,308,960 B2 · Adapting an utterance cut-off period based on parse prefix detection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,308,960 B2 - Document ID: US11308960B2 - Status: Granted - Kind: B2 - Application number: 16/824,308 - Filed: 2020-03-19 - Published: 2020-07-09 - Granted: 2022-04-19 - Earliest claimed: 2017-12-27 - Assignees: SoundHound, Inc. - Applicants: SoundHound, Inc. - Inventors: Patricia Pozon Aguayo; Jennifer Hee Young Zhang; Jonah Probell - Web page: https://patentgrep.com/patent/US11308960B2 ## CPC - G10L 15/22: Procedures used during a speech recognition process, e.g. man-machine dialogue - G10L 15/05: Word boundary detection - G10L 15/1822: {Parsing for meaning understanding} - G10L 25/78: Detection of presence or absence of voice signals (switching of direction of transmission by voice frequency in two-way loud-speaking telephone systems H04M9/10) - G10L 15/19: Grammatical context, e.g. disambiguation of the recognition hypotheses based on word sequence rules - G10L 15/30: Distributed recognition, e.g. in client-server systems, for mobile phones or network applications - G10L 2015/088: {Word spotting} - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING ## Abstract A processing system detects a period of non-voice activity and compares its duration to a cutoff period. The system adapts the cutoff period based on parsing previously-recognized speech to determine, according to a model, such as a machine-learned model, the probability that the speech recognized so far is a prefix to a longer complete utterance. The cutoff period is longer when a parse of previously recognized speech has a high probability of being a prefix of a longer utterance. ## Claims ### Claim 1 A method of adjusting a cut-off period for detecting an end of a sentence, the method comprising: receiving a plurality of spoken words; detecting periods of voice activity and periods of no voice activity within the plurality of spoken words; parsing the plurality of spoken words according to a first grammar and a second grammar to determine whether the plurality of spoken words are a complete parse according to the first grammar and a prefix to another complete parse according to the second grammar; accessing an NVAD cut-off period calculated from prior speech; and scaling the NVAD cut-off period in accordance with a prefix hypothesis numerical score. ### Claim 2 (depends on 1) The method of claim 1, further comprising producing the prefix hypothesis numerical score indicating a likelihood that the received plurality of spoken words is both: (a) the complete parse and (b) the prefix to the other complete parse. ### Claim 3 (depends on 2) The method of claim 2, wherein producing the prefix hypothesis numerical score comprises analyzing natural grammar rules determining that the received plurality of spoken words is a complete parse prefix. ### Claim 4 (depends on 3) The method of claim 3, wherein analyzing natural grammar rules comprises aggregating multiple grammar rules. ### Claim 5 (depends on 1) The method of claim 1, wherein scaling the NVAD cut-off period in accordance with the prefix hypothesis numerical score comprises scaling the NVAD cut-off period based on the plurality of spoken words being the prefix to the other complete parse. ### Claim 6 (depends on 1) The method of claim 1, wherein detecting periods of voice activity and periods of no voice activity within the plurality of spoken words comprises detecting inter-word pause lengths. ### Claim 7 (depends on 1) The method of claim 1, further comprising computing an average phoneme rate from the periods of voice activity and the periods of no voice activity within the plurality of spoken words; and wherein scaling the NVAD cut-off period comprises scaling the NVAD cut-off period based on the average phoneme rate and in accordance with the prefix hypothesis numerical score. ### Claim 8 A system comprising: a processor; and system memory coupled to the processor and storing instructions configured to cause the processor to: receive a plurality of spoken words; detect periods of voice activity and periods of no voice activity within the plurality of spoken words; parse the plurality of spoken words according to a first grammar and a second grammar to determine whether the plurality of spoken words are a complete parse according to the first grammar and a prefix to another complete parse according to the second grammar; access an NVAD cut-off period calculated from prior speech; and scale the NVAD cut-off period in accordance with a prefix hypothesis numerical score. ### Claim 9 (depends on 8) The system of claim 8, further comprising instructions configured to produce the prefix hypothesis numerical score indicating a likelihood that the received plurality of spoken words is both: (a) the complete parse and (b) the prefix of the other complete parse. ### Claim 10 (depends on 9) The system of claim 9, wherein instructions configured to produce the prefix hypothesis numerical score comprise instructions configured to analyze natural grammar rules to determine that the received plurality of spoken words is a complete parse prefix. ### Claim 11 (depends on 10) The system of claim 10, wherein instructions configured to analyze natural grammar rules comprise instructions configured to aggregate multiple grammar rules. ### Claim 12 (depends on 8) The system of claim 8, wherein instructions configured to scale the NVAD cut-off period in accordance with the prefix hypothesis numerical score comprise instructions configured to scale the NVAD cut-off period based on the plurality of spoken words being the prefix to the other complete parse. ### Claim 13 (depends on 8) The system of claim 8, wherein instructions configured to detect periods of voice activity and periods of no voice activity within the plurality of spoken words comprise instructions configured to detect inter-word pause lengths. ### Claim 14 (depends on 8) The system of claim 8, further comprising instructions configured to compute an average phoneme rate from the periods of voice activity and the periods of no voice activity within the plurality of spoken words; and wherein instructions configured to scale the NVAD cut-off period comprise instructions configured to scale the NVAD cut-off period based on the average phoneme rate and in accordance with the prefix hypothesis numerical score.