7. The method of claim 1 , further comprising: specializing the secondary ASR recognizer by using an adaptation grammar of structure and content appropriate to a putative span type, as determined by NLU processing, said adaptation grammar additionally including acoustic prefix words, acoustic suffix words, or both, as transcribed by the primary ASR recognizer to ensure high accuracy secondary ASR recognition in view of coarticulation effects in the processed utterance and potential imprecise determination of span start and end times; and correspondingly expanding said span to include said acoustic prefix words, acoustic suffix words, or both.
7. The method of claim 1 , further comprising: specializing the secondary ASR recognizer by using an adaptation grammar of structure and content appropriate to a putative span type, as determined by NLU processing, said adaptation grammar additionally including acoustic prefix words, acoustic suffix words, or both, as transcribed by the primary ASR recognizer to ensure high accuracy secondary ASR recognition in view of coarticulation effects in the processed utterance and potential imprecise determination of span start and end times; and correspondingly expanding said span to include said acoustic prefix words, acoustic suffix words, or both. 8. The method of claim 7 , further comprising: including acoustic prefix words, acoustic suffix words, or both within the adaptation grammar by preparing said adaptation grammar as a slotted grammar with appropriate one or more prefix slots, suffix slots, or both and populating said slots as appropriate with acoustic prefix words, acoustic suffix words, or both, as transcribed by the primary ASR recognizer.