All marriage green card supporting documents must be translated into English.
Although the government requires a translated document to be “certified,” it does not require the person performing the translation to be officially credentialed in translation services. In other words, the translator doesn’t need to be a professional, just competent in English and the foreign language in which the document was originally written.
While current immigration law allows applicants (and sponsors, if applicable) to be their own translators, the decision to accept a "certified" translation is always at the discretion of the immigration officer reviewing the documents. To avoid delays or complications applicants typically use professional translation services to translate documents.
Check out this resource article for more information about translating immigration documents.