In some countries, such as the Netherlands, France, Italy, or Québec (Canada) among others, they also retain and keep a minute copy of their instruments—in the form of memoranda—in notarial protocols, or archives. Notaries generally hold undergraduate degrees in civil law and graduate degrees in notarial law.
Yes, you may notarize a document in a foreign language. However, the Notary certificate on the document must be in English.
U.S. embassies and consulates provide notarial services like a notary public in the United States. A notary is someone who witnesses you sign a document. In countries that are part of the Hague Convention, get your document notarized by a local notary.
Signatures can be usually also notarized by a U.S. “Notary Public”, however in some cases an apostille is required as well. Please clarify beforehand with the German authority in question, to whom you need to submit the document, whether an apostille is additionally required.
You can go to a notary at any U.S. Embassy or Consulate. By getting a notarization at an embassy or consulate, you're required to make a personal appearance, meaning the person requesting the notarization must appear in-person.
The short answer is yes, notary publics are legally allowed to notarize documents from any state as long the notarial act is conducted within the geographical boundaries of the notary's state of commission.
Embassy and consular staff are authorized to notarize documents being sent to their home countries. If a foreign country requests a notarial act for a signer's document that a U.S. Notary isn't authorized to perform, the signer can contact a local consulate or embassy of the receiving nation for assistance.
And so, typically when you are here in the United States and you need a document notarized for your home country, a regular notary does not have the capacity to do that, but an International Civil Law Notary does and therefore, you have no reason to actually go to a foreign consulate.