1.2 International application filed in multiple languages
1.2.2 Request
The request (including any declaration contained in the request under Rule 4.17) may be filed with the EPO as receiving Office in any official language of the EPO (e.g. the request filed in German and the rest of the application in English).
R. 12.1(c)
GL/RO 59
If the request is not filed in an official language of the EPO, the applicant will be invited to correct the defect (Form PCT/RO/106) within two months of the date of the invitation.
If the applicant replies to the invitation within the prescribed time limit by submitting the translation in one of the official languages of the EPO, the international filing date will remain unaffected.
R. 26.3ter(c)
GL/RO 60