European patent applications can be filed in any language. However, if filed in a language other than an official language of the EPO (English, French or German), a translation into English, French or German must be filed within two months of the date of filing (Rule 6(1)). Such translation may be subsequently brought into conformity with the original text of the application (but see A‑VII, 6.2). For the procedure where the translation is not filed in time, see A‑III, 14.
Where the description is filed by reference to a previously filed application (see A‑II, 18.104.22.168) and the previously filed application used for the reference is not in an official language of the EPO, the applicant must also file a translation into one of those languages within two months of the date of filing. With regard to the procedure when the translation is not filed on time, see also A‑III, 14.
However, the use of a non-EPO language does not automatically qualify the application for a reduction in the filing fee. This is only available under certain circumstances (see A‑X, 9.2.1 and A-X, 9.2.2).