https://www.youngparents.com.sg/education/10-ways-help-your-shy-child-become-confident-speaker/ I did not enroll my gal into any school but I read articles and try to encourage her instead. Hope the article will help.
You can try those centres or schools that conduct speech and drama classes.
Go search the emcee academy by the Flying Dutchman
Hi... try My English School
British council
Hi can try LWS