The decisions set out below concern filings according to the EPC 1973, which, under Art. 80(d) EPC 1973, had to contain one or more claims in addition to a description (see now R. 40(1)(c) EPC). The application could only be filed in an official EPO language (Art. 14(1) EPC 1973) or, by persons benefiting from the "language privilege" as they are defined in Art. 14(2) EPC 1973, in an official language of a contracting state other than English, French or German ("admissible non-EPO language"). For the current scope of the "language privilege" see Art. 14(4) EPC and 5. below.
In J 7/80 (OJ 1981, 137) the Legal Board held that where documents making up an application were partly in an official language of the EPO and partly in another language which was an official language of a contracting state, then, for the purposes of deciding whether the application complied with Art. 14(1) or (2) EPC 1973, in accordance with Art. 80(d) EPC 1973, the significant language was that used for the description and claims. Other documents making up the application should normally be corrected by translation into that language.
In T 382/94 (OJ 1998, 24), the claims and description had been filed in German, but the drawings contained text matter in English. The board held that the EPC did not make the accordance of a filing date dependent on any text matter in the drawings being in a language in accordance with Art. 14(1) or (2) EPC 1973. If the drawings were filed in full on the date of filing, they formed part of the application as filed, even if they contained text matter in an official language other than the language of proceedings. There was nothing to prevent the application being amended on the basis of a translation of this text matter into the language of the proceedings.
According to J 18/96 (OJ 1998, 403), the requirements under Art. 80 EPC 1973 for according a filing date were not fulfilled if the description and claims were filed in two different official languages. However, if, notwithstanding this deficiency, the Receiving Section left the applicant for a considerable time in the justified belief that the application was validly filed, then his legitimate expectations might be cited as regards according a filing date.
Referring to J 18/96, the Legal Board explained in J 22/03 that under Art. 80(d) EPC 1973, the documents filed must contain a description and one or more claims in one of the languages referred to in Art. 14(1) and (2) EPC 1973, in order for a date of filing to be accorded. Art. 14(1), second sentence, EPC 1973 stated that European patent applications must be filed in one of the official languages. The principle that applications are to be monolingual could therefore clearly be inferred from that provision. Since Art. 80(d) EPC 1973 referred to that provision, accordance of a date of filing required that the description and the patent claim(s) be in the same (permitted) language.