What language should be used for oaths and declarations if the inventor understands English?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

According to the MPEP 602.06, if an inventor understands English, it is preferable to use English for oaths and declarations. The manual states:

“If the individual comprehends the English language, he or she should preferably use it.”

This preference for English, when possible, likely helps streamline the patent application process and reduces the need for translations. However, it’s important to note that the primary requirement is for the inventor to understand the language used, whether it’s English or another language.