4.1.4Language arrangements to assist applicants from certain contracting states 

4.1.008If you (or one of your co-applicants) have your residence or principal place of business in a contracting state that has a language other than English, French or German as an official language, or if you (or one of your co-applicants) are a national of such state but are resident abroad, you may file a European patent application and/or the request for examination in one of that state's official languages ("admissible non‑EPO language"). 

4.1.009If you are thus entitled to file the application or the request for examination in an admissible non‑EPO language and do so, a 30% reduction of the filing and/or examination fee applies if you, as an applicant, are a natural person, a small or medium-sized enterprise, a non-profit organisation, a university or a public research organisation. In order to benefit from the reduction, you must submit a declaration of entitlement at the latest by the time of payment of the (reduced) filing or examination fee. The declaration can be made directly in the request for grant of a European patent (EPO Form 1001; see point 4.1.013) or by filing EPO Form 1011, available on the EPO website (epo.org).

If you have co-applicants, each one of them must also be either a natural person or an entity according to the above definition and must declare so if you wish to benefit from the 30% reduction of the filing and/or examination fee. 

4.1.010If point 4.1.008 applies to you, at any time in the procedure after filing your application you may file any documents subject to a time limit in an official language of your state; but within one month of filing any such document you must submit a translation into the language of the proceedings.