In T 706/91 the appeal had been drawn up in accordance with R. 1(1) EPC 1973 in one of the official languages, namely German. The appellant had therefore cited passages from the disputed European patent's claims and description in that language, even though they had been drawn up in French as the language of the proceedings. The board decided that these references were admissible.
In its decision G 4/08 (OJ 2010, 572) the Enlarged Board of Appeal clarified that EPO departments cannot use, in written proceedings on a European patent application or an international application in the regional phase, an EPO official language other than the language of proceedings used for the application under Art. 14(3) EPC (thereby overruling J 18/90, OJ 1992, 511).
R. 4(1) EPC (cf. R. 2(1) EPC 1973) allows any party to oral proceedings to use an official language of the EPO other than the language of the proceedings, provided he either gives the EPO at least one month's notice or arranges for interpreting into the language of the proceedings. Under R. 4(5) EPC the EPO must, if necessary, provide at its own expense interpretation into the language of the proceedings, or, where appropriate, into its other official languages, unless such interpretation is the responsibility of one of the parties.
In T 34/90 (OJ 1992, 454) the respondent did not give notice that he wished to use another official language in the oral proceedings and also failed to provide interpretation. His representative argued that because he had lawfully used an alternative official language in oral proceedings before the opposition division, he should be allowed to use the same language in the hearing before the board. Although he did not actually say so, this plainly implied that appeal proceedings were simply a continuation of the first-instance (i.e. opposition) proceedings. From the principle that appeal proceedings were wholly separate and independent from first-instance proceedings for the purpose of deciding the admissibility of using an alternative official language under R. 2(1) EPC 1973 - and for other procedural purposes - the board inferred that a party could use such a language in oral proceedings before it only if he again gave the requisite notice (see also communication from the Vice-President of DG 3, Supplement to OJ 1/2013, 71).
In T 774/05 the board stated that R. 2(1) EPC 1973 (R. 4(1) EPC) implied that a party could choose to use one of the official languages set out in Art. 14(1) EPC 1973 and was entitled to speak and hear that language. However, a party had to be clear as to which official language it wished to use. The party then had a right to both speak and hear in that language, so long as the conditions of R. 2(1) EPC 1973 were fulfilled. The party did not, however, have a right to have a language in which it would speak and a different language in which it would listen.
In T 418/07 the respondent announced that it would use German at the oral proceedings (language of proceedings being English) and requested the board to provide translation from German into English for the benefit of one of its employees who would attend the oral proceedings and who did not speak German. The board took the view that a party which elected to use a language which was not understood by one of its own representatives or employees could not for that reason request a free translation. The board could not provide translation merely to suit the convenience of a party.
See also T 131/07 and T 2422/10, which deal inter alia with interpretation requests for the benefit of accompanying persons. The matter of the language arrangements in oral proceedings in relation to an accompanying person was also dealt with in R 3/08 (see under IV.E.9.2.9 b) (vii)).
On the costs of interpreting during oral proceedings see further III.C.5.2.