1. A method of training a transformation component using a trained acoustic model comprising first parameters having respective first values established during training of the acoustic model using first training data, the method comprising: using at least one computer processor to perform: coupling the transformation component to a portion of the acoustic model, the transformation component comprising second parameters; and training the transformation component by determining, for the second parameters, respective second values using second training data input to the transformation component and processed by the acoustic model, wherein the acoustic model retains the first parameters having the respective first values throughout training of the transformation component.