LANGUAGE schemes which could eventually make students trilingual were backed yesterday by senior government education advisers. An expansion of schemes to teach English and Putonghua to primary and secondary students was called for at a Board of Education monthly meeting. Both the pilot introduction of Putonghua lessons and the employment of expatriate English teachers had proved successful, board members said after the meeting. No language should take priority, member Ms Sansan Ching Teh-chi said, but children should be given the opportunity to learn different languages. Experimental teaching of Putonghua, which began in selected primary schools in 1981 and spread to secondary schools in 1984, had shown the lessons were satisfactory and feasible, said Ms Ching, who is also the director of the Hongkong Council of Early Childhood Education and Services. But teachers are often struggling with the language themselves and need more training to gain confidence and prepare better lessons, she added. Students' speaking skills were far behind their ability to listen and understand Putonghua, partly because of the teaching but also because they rarely heard the language spoken outside of the classroom. ''It would be good if it could be offered as an optional subject in more schools but it is difficult to get proper time in the curriculum when there are so many other subjects,'' Ms Ching said. ''We support the pilot schemes and hope the Government will continue to encourage teachers to go for Putonghua training.'' The board also decided to voice its approval of the scheme to bring native English-speaking teachers to Hongkong to improve the standard of English in schools. Member Mrs Minnie Lai Wei Kit-lin said it was vital to raise English standards. Expatriate teachers had been welcomed by almost every school participating in the Permanent Expatriate English Language Teacher Scheme in which the Government provides housing allowances, medical coverage, travel expenses and other benefits for the teachers, she said. ''We must get better teachers. According to the latest survey only 20 per cent of English teachers have majored in English and that is not good enough,'' she said. But Mr Mervyn Cheung Man-ping, secretary for the Hongkong Association for Continuing Education, was concerned the expatriate teachers might become a ''privileged minority'' in light of their extra benefits. The financial implications of importing several hundred more overseas teachers must be studied carefully, he said.