1. A method for performing progressive display rendering of machine-translated text, the method comprising: submitting a plurality of requests for translating displayed text of a displayed document from a source language to a target language, each of the plurality of requests including at least one sentence of text, and ones of the plurality of requests being submitted independently of receiving a corresponding response to an immediately preceding submitted request; receiving translated responses including text in the target language, each of the translated responses corresponding to a respective one of the submitted plurality of requests; determining whether text corresponding to respective received ones of the translated responses is currently being displayed; and replacing only portions of the displayed text in the source language with corresponding ones of the text included in the respective received ones of the translated responses as the respective ones of the translated responses are received, when the determining determines that the text corresponding to the respective received ones of the translated responses is currently being displayed, wherein the method is implemented by a processing device.