PCT Newsletter

July-August 2026 | No. 07-08/2026

Practical Advice

Requirement for translations of the international application during the international phase

Q: Our company often files PCT applications in Spanish. Several of the International Searching Authorities (ISAs) specified by the receiving Offices that we use do not perform searches in Spanish. Will we need to furnish any translation during the international phase?

A: Each receiving Office (RO) determines which language(s) it accepts for applications filed with it (PCT Rule 12.1). It may accept any language. When applicants have already filed a national application in their home country and then file a subsequent PCT application on the same invention with a receiving Office that accepts that same language, they may typically use their earlier application and simply add a filled-in PCT request form. In other words, applicants may generally obtain an international filing date without having to first translate the earlier application before filing their PCT application.[1]  For details of the languages accepted by each RO, refer to Annex C of the PCT Applicant’s Guide. 

Each RO must accept at least one language which is both a language accepted by the ISA to perform the international search (or by at least one of the ISAs, if the applicant may choose among two or more ISAs)[2] and a language of publication (PCT Rule 12.1(b)). Depending on the language in which the application is filed, applicants may thus have the option of filing in a particular language without having to furnish any translation during the international phase. This will be the case, for example, if you file the application in Spanish with the National Institute of Industrial Property in Chile and choose an ISA which performs searches in Spanish.[3]  The PCT request will always be in a “language of publication” that the RO accepts (PCT Rule 12.1(c)), with the data being used for the front page of the published application. For details of the languages accepted by each ISA, refer to Annex D of the PCT Applicant’s Guide. 

If you file the PCT application in a language that is not one in which the competent/chosen ISA performs an international search, then within one month of the RO receiving your application, you must furnish a translation into a language that is accepted by the ISA concerned; for details, refer to PCT Rule 12.3. 

For example, if you file the application in Spanish with the National Institute of Industrial Property in Chile and wish the Ministry of Intellectual Property of the Republic of Korea (MOIP) to perform the international search, you will need to furnish a translation into Korean or English.[4]  Please note that for the original disclosure, it will be the language in which the application was filed that is relevant. Accuracy of the translation is the applicant’s responsibility (PCT Article 46). Any mistake in the translation would generally need to be remedied in the national phase under applicable national procedures. 

The ten languages of publication under the PCT are Arabic, Chinese, English, French, German, Japanese, Korean, Portuguese, Russian and Spanish (PCT Article 21(4) and Rule 48.3(a)). If a PCT application is filed in one of these languages, it will be published in that same language, irrespective of whether any translation has been furnished after the international filing date for the international search. If the application is filed in Spanish, it will be published in Spanish; under current procedures you cannot choose to have it (also) published in any other language of publication. 

If the application is published in a language other than English, the International Bureau will translate into English the title, abstract and the international search report (or declaration under PCT Article 17(2)(a) that no search report will be established), and will publish that English translation in addition to the other published language version (PCT Articles 18(3) and 21(4), and Rules 45 and 48.3(c)).

In most cases where a PCT application has been filed in a language which is not a publication language and a translation has been furnished for the international search, that translation will also need to be in a language of publication and will be used for international publication. In a few cases a PCT application may be filed and searched in a language which is not also a language of publication, in which case the applicant will need to furnish a translation specifically for the international publication under PCT Rule 12.4; this might be the case, for example, for applications filed and searched in Danish, Finnish, Norwegian or Swedish. 

Which language(s) are accepted by an Office is typically one of the criteria to consider in choosing an RO or ISA at the time you file the PCT application. Other possible criteria include fees payable, searchable subject matter, restrictions regarding number of applications, familiarity with a particular office or its efficiency of processing, acceptance of non-conversion files, applied safeguard procedures – and more.

Details relating to the languages to be used for filing any amendments under PCT Article 19, rectifications of obvious mistakes under PCT Rule 91.1 or corrections of formal defects in translations can be found in PCT Rule 12.2. 

Further information can be found in the Practical Advice in the following issues of the PCT Newsletter:

  • 07-08/2024: Mixed languages used in an international application
  • 10/1998: Filing of an international application in a language which is accepted by the receiving Office but which is neither a language accepted by the competent International Searching Authority nor a language of publication

[1] If the description and claims of an international application are not in a language accepted by the RO, that Office will not be a competent RO and will transmit the application to the International Bureau of WIPO as receiving Office (RO/IB) under PCT Rule 19.4.

[2] It is the RO that determines which ISA(s) are competent for applications filed with it; refer to PCT Rule 35 for details, including for applications filed with RO/IB.

[3] At time of writing, this would include the National Institute of Industrial Property (Chile), the National Institute of Industrial Property (Brazil) and the Spanish Patent and Trademark Office (OEPM).

[4] Note that the search fee will be different depending on which of these two languages you choose; refer to PCT Applicant’s Guide, Annex D (KR).

​​​​​​​Back to Contents page