1. A method for speech recognition in a motor vehicle, comprising: receiving voice inputs from a user at a vehicle-internal processing device, the voice inputs being received via a vehicle-internal capture device; supplying by the processing device: at least one voice input to a vehicle-internal onboard speech recognition unit for producing a first recognition result of spoken text; at least one voice input to a vehicle-external offboard speech recognition unit for producing a second recognition result of spoken text; receiving the first recognition result at the processing device from the onboard speech recognition unit; receiving the second recognition result at the processing device from the offboard speech recognition unit; and using the first and second recognition results by the processing device as a basis for automatically ascertaining recognition text corresponding to the voice inputs, wherein the processing device selects and activates based on a control parameter, one of the following modes for speech recognition purposes: sequential speech recognition in which keyword recognition is first performed using the onboard speech recognition unit, and then the first recognition result is used to extract at least one recognizable component and at least one unrecognizable component, the at least one recognizable component is used to select the vehicle-external offboard speech recognition unit among a plurality of vehicle-external offboard speech recognition units, and the at least one unrecognizable component is then supplied to the selected vehicle-external offboard speech recognition unit to produce the second recognition result; parallel speech recognition in which a single voice input is supplied in parallel to the onboard speech recognition unit and independently thereof to the offboard speech recognition unit; complete onboard speech recognition using the onboard speech recognition unit; and complete offboard speech recognition using the offboard speech recognition unit, and wherein the control parameter on which the processing device bases selection and activation, is a parameter relating to a current operational scenario, the operational scenario indicating what operator control process is meant to be performed by the user by way of the recognition text.