A khutbah is meant to convey the message in the language of the people to whom it is delivered.The purpose of the khutbah cannot be achieved if it has been delivered in a language other than that of the audience. Almighty Allah tells us in the Qur’an:[We sent not a messenger except (to teach) in the language of their nation in order to make (things) clear to them](Ibrahim 14:4).So, if the audience knows no language other English, then, there is nothing wrong in delivering the Friday khutbah in English.
Prominent Muslim scholar Sheikh Muhammad Iqbal Nadvi, director and imam of Al-Falah Islamic Center, Oakville, Ontario, Canada, states: In my understanding, there is no condition that the Friday khutbah must be delivered in Arabic; it is different from the daily Prayers that are supposed to be said in Arabic. Prophet Muhammad (peace and blessings be upon him) delivered the Friday khutbahs in Arabic because the audience were Arabs. During the long history of Islam, the Friday khutbahs have been delivered in other languages because they are meant to convey the message in the language the people understand.
Having said this, the Friday khutbah should contain words of dhikr (remembrance of Allah) such as praising Allah, praying for peace for the Prophet, and reciting some verses from the Qur’an. So if the imam did those in Arabic, he would be already fulfilling the minimum requirements of the khutbah, and therefore the mainstream language could be English, without any problem.