Yodel along!
Yodelling, long seen as a caricature of out-dated Alpine kitsch, is undergoing a renaissance.
The sound of 'yo yo yo lue lu' conjures images of remote valleys and snowy peaks, but every Friday the distinctive notes drift through a classroom window and across the Swiss city of Zug's industrial district.

Yodelling, long seen by outsiders as a caricature of out-dated Alpine kitsch, is undergoing a renaissance among an urban generation seeking to reconnect with their roots.
"It's traditionally Swiss," says 36-year-old architect Eva Guhl, echoing other members of the evening school beginners group as they explain what has drawn them to the classroom on Metal Street every Friday evening for the last three months.
"It's a wonderful feeling when you let it all out," she said. "In pop songs you can hold yourself back, but not with yodelling."
The 1965 film "The Sound of Music", starring Julie Andrews, used yodelling, goat-herds and lederhosen in what became one of the world's most successful musicals.
Unlike lyrical singing, yodelling is a non-verbal technique which plays on sharp transitions from low "chest" notes to high or "head" notes -- stringing together single syllables with an energetic and unique twang.
The technique may have its origin centuries ago as a far-carrying communication cry between Alpine shepherds in remote mountain communities, but it endures today.
Despite the revival in urban Zug, Swiss and Austrian yodelling is also heard in folklore festivals, tourist restaurants or sound recordings.
Austria's Eurovision Song Contest entry this year was a distinctive fusion of yodelling and salsa.
Last month, a record 180,000 visitors thronged a yodelling festival in Aarau -- a Swiss urban outpost more known for its shopping centres and tower blocks.
YODELLING REVIVAL
Professional yodeller Rita Ehrler, 48, attributes the recent rise in yodelling's popularity to a longing for homeliness and reassurance in the face of social problems and rapid change.
"Yodelling simply gives you a feeling of warmth and security. It's a Swiss thing," she says, flanked by her 20-year-old daughter Nicole, the fourth generation of yodellers in the family.
Rita Ehrler learnt to yodel from her grandfather in the central Swiss village of Ibach Schwyz, home to the Swiss army knife and picture-postcard views of green meadows sweeping up to craggy snow-capped peaks.
It is a far cry from the classroom where she runs the evening course for the Migros Klubschule, the educational arm of a supermarket-lifestyle conglomerate which also offers Zug-dwellers courses in hip hop or latino dance aerobics.
Although one fifth of tiny Switzerland's population are foreigners and the export-led economy depends on links with abroad, foreign influences have done little to erode stout national pride among the country's Germanic majority.
Yodelling itself often forms the refrain to traditional songs about nature, communities or God which are sung in Swiss German -- a bastion of Swiss identity but a linguistic quagmire to non-native speakers."It's not the sort of music I listen to at home," acknowledges 23-year-old nursery school teacher Manuela Brunner. "But I like it."