Loud-mouthed pupils could win their schools up to pound;3,000 if they enter the Jack Petchey Foundation Speak Out challenge which has been targeting London schools.
The project aims to increase students' confidence by training them in public speaking and speech writing. Lessons worth pound;600 each are being offered free to 25 pupils at every state school in the capital.
Winners of the 32 borough finals will enter the grand final next July when they stand to win pound;3,000 and a holiday for four to Portugal.
Sean Kennedy, regional director of SpeakersBank, which runs the training, said: "It's amazing to see previously monosyllabic pupils getting up and speaking.
"Many people expect teenagers to be interested in sex, drugs and music but in general they want to talk about very serious issues like bullying, racism and poverty."
* For more information, visit www.jackpetcheyfoundation.org.ukmajor-grants