Teenagers in uniforms strumming guitars and singing self-composed songs in lecture theatres. Radio DJs receiving cassette tapes sent in by aspiring singers. A singing contest to choose the theme song of The Awakening, the landmark Channel 8 drama serial.

Ah, xinyao.

The term was coined in 1982 to refer to the songs created by Singaporeans and has since come to be shorthand for the grassroots movement in which young people here wrote and sang their own songs.

It was led largely by a special group of people - the last generation of young people educated in Chinese-medium schools, as an excellent documentary on xinyao points out.

Titled The Songs We Sang, the two-hour documentary directed by former journalist Eva Tang premiered at the Esplanade Theatre on Nov 29 as part of the just-concluded Singapore International Film Festival. All its 1,427 tickets were sold out.

The last few years have seen many xinyao reunion concerts and dramas inspired by xinyao, such as the feature film The Girl In Pinafore (2013) and the recently concluded Channel 8 drama, Crescendo.

But the documentary by Tang and her team is a special valentine to the songs written and sung by Singaporeans. Not only does it tug at the heartstrings with familiar faces, voices and tunes, but it is also likely to be the most thorough attempt yet to delve deep into the origins of this popular cultural movement.

The irony, as the film noted, was that the roots of the movement were fuelled in a way by the sense of despair surrounding Chinese education, as it prepared to take a bow in Singapore in the late 1970s.

A pivotal event was the closure of Nanyang University (Nantah), which was merged in 1980 with the University of Singapore to become the National University of Singapore.

Set up in 1956 as the first Chinese-medium university in South-east Asia, it faced declining enrolment as more parents opted for English-medium schools. Chinese-medium schools were phased out by 1987.

Before budding campus singers struck a chord in the 1980s, the last Nantah students were already composing their own poetry songs and performing them at concerts.

With gloom hanging over their and the university's future, many channelled their energies into creative work, expressing their melancholia and sadness in songs.

Some went on to become teachers, or media or music industry workers in a position to groom budding singers and songwriters.

For instance, Dawn Gan had her teacher, a Nantah alumnus, to thank for a chance to perform at a concert as a student at National Junior College in 1982. Her performance of How To Tell You (Ru He Dui Ni Shuo), written and composed by Lin Weiling, paved the way for her to become one of xinyao's best-known faces.

The footage of Gan's memorable performance is included in the documentary, a treasure trove of sounds and images of early xinyao performances.

The documentary traces the development of xinyao not only from the experiences of the last Nantah students, but also the generation caught in between languages.

These were students from Chinese-stream secondary schools who had to switch to English for pre-university, with the impending closure of Nantah. This generation of students who can speak and write well in Chinese are an "endangered species", said director Tang.

Among them were the likes of singer Eric Moo, who was from a Chinese-medium secondary school. He played a key role in the xinyao movement, writing songs and becoming one of its more popular singers.

Moo recalls how his Jurong Junior College schoolmates from English schools looked enviously at him and his group from Chinese schools for their camaraderie and songwriting flair.

The documentary does not just look at the singers and songwriters, but also gives viewers a sense of the wider social milieu by including excerpts from news programmes in the 1970s and 1980s, including recordings of former Chinese school teachers trying to teach in English.

It looks at media figures who helped popularise xinyao, such as radio host Lim Cher Hui, who introduced a radio segment for local compositions, as well as how Channel 8 drama serials helped to boost the popularity of these songs when they used them as theme songs.

For example, a television songwriting competition was held to choose the theme song for The Awakening (1984). The song eventually chosen, composed by Lan Zhaopang, with lyrics by Muzi, remains a tune that many people here can remember.

Born when Chinese education was on the wane in Singapore, the xinyao movement has helped to sustain interest in the Chinese language and laid the ground for later Singaporean Mandopop singers such as Stefanie Sun and JJ Lin.

While the two-hour documentary ends without examining how the xinyao movement petered out by the 1990s, it is a loving tribute to a grassroots movement fuelled by youthful idealism and a wistful remembrance of things that were lost with the demise of Chinese schools.

Tang and her team wish to release the documentary in theatres, but the challenge is to clear the copyright for the many songs and music videos in it. They hope theatres or kind-hearted individuals can help.

"Our dream is to let as many Singaporeans as possible watch it," said Tang. Hopefully, their dream comes true, for it is a documentary that deserves a wider audience.

•For more information about the documentary The Songs We Sang, go to www.thesongswesang.com