37 CFR §1.69

1. (a)Whenever an individual making an oath or declaration cannot understand English, the oath or declaration must be in a language that such individual can understand and shall state that such individual understands the content of any documents to which the oath or declaration relates.
2. (b)Unless the text of any oath or declaration in a language other than English is in a form provided by the Patent and Trademark Office or in accordance with PCT Rule 4.17(iv), it must be accompanied by an English translation together with a statement that the translation is accurate, except that in the case of an oath or declaration filed under § 1.63, the translation may be filed in the Office no later than two months from the date applicant is notified to file the translation.