The European Patent Office has three official languages: English, French and German. If a International (PCT) application is filed in one of these languages, can it be changed to another of them on entry into the European phase?
The Enlarged Board of Appeal says the answer is "No" (G04/09).
Upon entry into the European regional phase, the applicant of EP02759818.4 requested to change the language of the proceedings from French to English and at the same time filed an English translation of the original French application on which the examination proceedings should be based. This request was rejected and the applicant appealed. The responsible Board of Appeal referred the issue to the Enlarged Board of Appeal, which ruled not only that the official language of an application cannot be changed, but also that EPO departments must use the original language in written proceedings.
An applicant may still file arguments in an another official language of the EPO (Rule 3 (1) EPC) and may also use another official language in oral proceedings (Rule 4 (1) EPC).
International corporations with research centres in French and German speaking countries (France, Belgium, Luxembourg, Germany, Austria and Switzerland) may prefer to first file in the local language at a national patent office, but should consider their choice of language in good time before the date for PCT filing.
At Jenkins, our Munich office is able to prosecute patent applications filed in German across a wide range of technical expertise, and in London we have qualified native French staff who can handle applications filed in French.