Befor khutba

Asalam mu alaikum mufti saab ,Can u tell me the law on the english sermon or lecture befor the imam stands on the mimbar .One person told me thats bidah and haram to have a third khutbah n the day of juma .And its not the practise of any of the previous scholars nor its proven from kitab and sunnah .Please reply in detail .Jazak Allah khair .