LOCAL showbiz stars will play the role of language ambassadors in a five-minute programme produced by the Television Division of RTHK to help young listeners brush up on their Cantonese pronunciation skills. Called the ''Cantonese Language Programme - Proper Cantonese Pronunciation Operation'', the programme will feature entertainment personalities such as Aaron Kwok, Roman Tam, Hacken Lee, Cheng King-kei, Edmond Leung Hon-man, Leo Koo Kui-kei, Liz Kong Hei-man, Ian Hung Kin-wah and Little Pak-lam. At a recent programme launching ceremony, the participating artistes demonstrated the proper and improper usage of various Cantonese syllables. Assistant director of broadcasting (TV) Maria Wan said: ''Training in proper Cantonese pronunciation is not available in most schools. In view of this, RTHK decided to produce a 20-part series in which proper pronunciation of Cantonese will be taught through demonstrations by artistes.'' Artistes invited to act as ''Proper Cantonese Pronunciation Ambassadors'' also included Leon Lai, Jacky Cheung, Sandy lam, Vivian Chow, Michelle Reis and Kenny Ho. The programme will be screened at 6.10 pm on TVB Jade and 7.55 pm on ATV Home every weekday. It will also be broadcast at 11 am in What a Nice Day and 3.30 pm in Newsrama on RTHK Radio 1 at 7.30 am in Morning Suite and 7.30 pm in Open Line, Open View on RTHK Radio 2, and 7.30 pm in Education Programmes on RTHK 5.