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. 9. The method of claim 7 , further comprising: deriving the proper name entities defining structure and content of the adaptation grammar used to specialize the secondary ASR recognizer from any of: (a) business names resulting from a search; (b) business names, personal contact names or both retrieved from any of a personal phone book, a personal calendar, or both; (c) contents of a music library, including artist names, song names, album names, and genre names; (d) contents of a video library, including actor names, director names, and genre names; (e) word sequences that the user has identified as personally significant; and (f) any combination of the foregoing.