1. A machine-implemented method, comprising: at an electronic device with one or more processors and memory: obtaining a document including text; receiving, from an automatic language identifier service, a first language identification for the document; in response to receiving the first language identification, automatically invoking a modifying operation; performing the modifying operation on the document in accordance with the first language identification; determining, based at least in part on results from the modifying operation, whether the first language identification for the document is correct, wherein the results from the modifying operation include at least one of the amount of errors or the nature of the errors associated with the modifying operation; in accordance with a determination that the first language identification is correct, providing the first language identification to a user application; in accordance with a determination that the first language identification is incorrect, determining a second language identification of the document, and performing a modifying function on the document in accordance with one or more alternate languages different from the first language, wherein the second language identification of the document is determined based at least in part on the results from performing the modifying function on the document in accordance with the one or more alternate languages.