The Hakka are a community whose ancestors moved to Taiwan many generations ago. Today the Hakka language is spoken alongside Mandarin Chinese and Taiwanese in many towns. About one in six people in Taiwan has Hakka family roots. The northern hills of Hsinchu and Miaoli are home to many Hakka villages.
The mountain songs began as a clever way for workers to talk to each other across a hillside while still doing their jobs. Imagine you are picking tea leaves on one slope and your friend is on the other slope a few hundred metres away. You can't shout a whole conversation. But you can sing - your voice carries beautifully across the valley.
The songs are often funny. Sometimes one singer sings a question, and waits for the other to reply with a clever answer. Many of the words rhyme. There are love songs, farming songs, weather songs and silly children's songs. New songs can also be made up on the spot - that is called 'improvising'.
Today, Hakka mountain songs are taught in schools and performed at festivals. Some Taiwanese pop singers blend the old songs with modern music, so children grow up hearing them again in fresh new ways. There are even singing competitions where pupils sing the same song their great-great-grandparents might have sung.