1. A method comprising: identifying, based on an expected demand for speech recognition, a main speech recognizer and a supplemental speech recognizer; beginning to process a recognition task using the main speech recognizer, to yield main results; and upon determining that the supplemental speech recognizer is idle: assigning the supplemental speech recognizer to the recognition task based on an actual demand for speech recognition resources; continuing to process the recognition task using the supplemental speech recognizer, to yield supplemental results; and combining the main results and the supplemental results.