An international patent application (e.g., PCT application) can be filed in any language which the receiving Office accepts. If you file your application in a language which is not accepted by the International Searching Authority (ISA) that is to carry out the international search, you will be required to furnish a translation of the application for the purposes of international search. Receiving Offices are, however, obliged to accept filings in at least one language which is both a language accepted by the competent ISA that is to carry out the international search and a "publication language", that is, one of the languages in which international patent applications are published (e.g., Arabic, Chinese, English, French, German, Japanese, Korean, Portuguese, Russian, and Spanish). Thus, there is always the option of filing your international patent application in at least one language from which no translation is required for either PCT international search or publication purposes.
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