Natural or legal persons having their residence or principal place of business within an EPC contracting state having a language other than English, French or German as an official language, and nationals of that state resident abroad, may file documents which have to be filed within a time limit in an official language of that state ("admissible non-EPO language"). For example, an Italian or Swiss applicant may file a reply in Italian to a communication from the examining division issued under Art. 94(3).[Art. 14(3); Art. 14(4); ]

A translation of a document filed in an admissible non-EPO language into an official language of the EPO must be filed within a non-extendable period of one month (Rule 6(2)). However, if the document is a notice of opposition or appeal, or a petition for review (Art. 112a), the period extends to the end of the opposition or appeal period or the period for petition for review, if this period expires later. The translation can be into any of the EPO's official languages, regardless of the language of the proceedings.[Rule 6(2); ]