13. The processing device of claim 9 , wherein: the displayed text includes text in a source natural language, the processing of the displayed text includes machine-translation of the displayed text from the source natural language to a target natural language, and each of the plurality of requests for processing displayed text includes one or more complete sentences.
9. A processing device comprising: at least one processor; and a memory connected to the at least one processor, the memory comprising: instructions for submitting a plurality of requests for processing displayed text, ones of the plurality of submitted requests being submitted independently of receiving a corresponding processing response to an immediately preceding submitted processing request; instructions for receiving respective processing responses including changed or annotated text corresponding to respective ones of the submitted plurality of requests; instructions for determining whether text corresponding to the respective received processing responses is currently being displayed; instructions for replacing only portions of the displayed text corresponding to the changed or annotated text in respective ones of the received processing responses as each of the respective ones of the received processing responses is received, when the determining determines that the text corresponding to the respective ones of the received processing responses is currently being displayed; and instructions for discarding the respective ones of the received processing responses as the respective ones of the received processing responses when the determining fails to determine that the text corresponding to the respective ones of the received processing responses is currently being displayed.