1. A file processing method applied to an operating system, the file processing method comprising: packaging a first package file which supports a plurality of language versions into a plurality of first single-language package files, wherein the plurality of first single-language package files correspond to the plurality of language versions, respectively; wherein names of the plurality of first single-language package files are strings corresponding to a name of the first package file and language codes related to the plurality of language versions; adding the plurality of first single-language package files to a plurality of language packages, respectively; when changing a language version of the application to a specific language, searching a system language package corresponding to the specific language in a system file hi a framework layer; when it is unable to find the system language package corresponding the specific language in the system file in the framework layer, searching the language package corresponding to the specific language in the plurality of language packages; and loading the language package corresponding to the specific language.