Community leaders say the exclusive use of Urdu by some Muslim clerics, including a number who speak no English, means sermons denouncing violent militants are not understood by many British-born Muslims.
The comments followed reports that two teenagers from Dewsbury have travelled to war-torn Syria.
The 17-year-olds, Hassan Munshi and Talha Asmal, both from Dewsbury, are thought to have entered the country after travelling to Turkey on March 31.
They were last seen by their families on the day they are believed to have flown from Manchester to Dalaman.
Mehboob Khan, former leader of Kirklees Council and an adviser to the government on counter-terrorism, said: “All of the mosques I know preach the right message but most young people go through a phase where they are rebellious because that’s part of growing up.
“We need to ask imams to give their sermons in both English and Urdu. Far too many imams solely rely on Urdu.”
Arif Ahmad, president of the Ahmadiyya Muslim Community Association in Dewsbury and Batley, said it was essential that imams made themselves understood to young people.
He said: “If an imam doesn’t speak English and the main language that these young people converse in is English there’s going to be a distance between them.”
Kirklees Council chief executive Adrian Lythgo said: “We need to talk openly about these risks that are posed to our young people, and to work together to protect them.
“Communities and families can contact police about anyone they feel may be vulnerable. This includes anyone who is showing signs of becoming radicalised, who may have returned to the UK from Syria or may be planning to go to Syria or another conflict zone.”