15. The computer-implemented method of claim 9 , further comprising ranking the first interpretation and the second interpretation based at least partly the first score and the second score, wherein the first interpretation is ranked higher than the second interpretation, and wherein selecting the first interpretation comprises selecting a highest-ranked interpretation of the text.
9. A computer-implemented method comprising: under control of one or more computing devices configured with specific computer-executable instructions, receiving text corresponding to a request of a user; processing the text in a first natural language understanding (“NLU”) module to generate a first interpretation of the text, and in a second NLU module to generate a second interpretation of the text, wherein the first NLU module is associated with a first domain, and the second NLU module is associated with a second domain, wherein the first interpretation is associated with a first score indicative of a confidence in the first interpretation, and wherein the second interpretation is associated with a second score indicative of a confidence in the second interpretation; selecting the first interpretation based at least partly on the first score and the second score; and generating a response based at least partly on the first interpretation.