T 2652/22 and T 1787/16: Language of proceedings

Key points

• The application was filed in 2006. The patent was granted in 2013. The OD issued its first decision in 2016. The Board set it aside in 2021 in the first appeal. The OD issued its second decision in 2022. The second appeal decision was issued in 2025.
• Actually, the first appeal decision (T 1787/16) is more interesting. The first OD decision included citations of the opponent's submissions (in English), whereas the language of the proceedings was German. The Board found this to be a twofold substantial procedural violation. First, citations of the parties’ arguments cannot replace the reasoning of the OD under Rule 111(2) in the manner that occurred in the case at hand.
• Second, (and obiter, see point 12 of the reasons), the decision should have contained translations of the citations in the language of the procedure, i.e., German. In fact, the EPO may only use the language of the procedure in the written decision, with limited exceptions (e.g., for terms such as 'ex officio', and when citing evidence).
• T 1787/16, in translation: "Therefore, for proceedings under the EPC, too, applying Article 125 EPC and the overall analogy it prescribes, it can be deduced from the procedural principles of the Contracting States that there is only very limited scope for using a language other than the language of the proceedings in the decision, namely only to the extent that it is necessary to answer procedurally relevant questions of fact, evidence, and law. This includes the verbatim quoting of foreign-language documents (both technical and non-technical) and of written and oral statements by witnesses, experts, or parties in the context of the evaluation of evidence, or—generally speaking—in the context of assessing the probative value and content (interpretation) of documents."
• • My analysis is that the Board derived the main principle that a procedure has a single language of procedure, which must be used exclusively unless an exception applies. The liberal regime of  Rule 3(1) EPC ("In written proceedings before the European Patent Office, any party may use any official language of the European Patent Office") is, therefore, an exception and applies only to the parties, not to the EPO.  
• In the current second appeal decision, the Board also finds a procedural violation: the list of cited documents is not included in the decision. However, the Board does not remit the case and examines the patent on the merits.
• Interestingly, the first OD decision was to reject the opposition. In the second decision, the OD, with a different composition, had decided to revoke the patent. The proprietor's appeal is dismissed.

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• EPO 

The link to the decision can be found after the jump.

https://www.epo.org/de/boards-of-appeal/decisions/t161787du1

https://www.epo.org/de/boards-of-appeal/decisions/t222652du1