What is the ruling on saying "Ameen" to the preacher's supplication if part of it is in a language the congregants do not understand?

The fundamental principle is that the preacher makes supplications for good during the Friday sermon, and your saying "Ameen" to his supplication, even if you do not understand what he is saying, does not harm you. It is hoped that the good will encompass you through your saying "Ameen." Ibn Taymiyyah said: "Supplication is permissible in Arabic and in other languages. Allah Almighty knows the intention and purpose of the supplicant, even if his tongue is not articulate." Saying "Ameen" to a supplication is itself a supplication and a Sunnah. It is narrated from Ibn Abbas that the Prophet, peace and blessings be upon him, said: "The Jews have not envied you for anything as much as they have envied you for Ameen; so say 'Ameen' frequently." And he, peace and blessings be upon him, said: "No group gathers, and some of them supplicate while the rest say 'Ameen,' except that Allah answers them."