When we first decided to make Martin Pescador (Kingfisher), a short eco-film entirely in Spanish, I naively imagined that the linguistic challenges would be the greatest we would face. I was wrong. On location in the nearby woods, our nine-year-olds had to contend not only with a hay fever epidemic, but also a steady stream of interested dogs, oblivious joggers and bell-ringing cyclists, along with two large - but gracious - horses.
The sun was shining. The poppies were in full bloom. School was out; we had closed our books. We were being Spanish children on a field studies trip in search of the elusive kingfisher. But the director, a freelance colleague, did not like my opening scene: it was too scripted. He wanted the camera to come across the children playing "naturally".
It was the actors themselves who improvised the solution, launching energetically into Roca, Papel, Tijeras (Scissors, Paper, Stone), followed by Correquetepillo (Catch). It was a moment of epiphany. Not only were all those things learned in the classroom useful, but they had been thoroughly assimilated, too.
As the day rolled on, more radical improvisation was required. Charles had to leave two-thirds of the way through filming, forcing us to recast him as a drop-out. When the bird-spotters are interrupted by a posse of lager-fuelled louts, causing them to scatter like a flock of startled sparrows, he duly does a runner. Emerging timidly from hiding, the others assume civic responsibility for clearing up the mountain of litter left by the villains who have spoiled the beauty of the forest.
The six-minute film was triggered by a competition run by the Spanish Embassy, and chimed harmoniously with the school's first ever week of dedicated environmental activities. It provided the ideal opportunity to put the theory of integrated learning into practice, with the added bonus of an early apprenticeship in film studies.
The children were essentially playing themselves: Charles really is quick-witted, in a hurry, perpetually in motion. The film is punctuated with his impatient cry: "Vamos a jugar al futbol!" ("Let's go and play football!")
We returned home from the shoot grubby and exhausted, legs scratched and half a tube of Anthisan down. We may have stumbled over the occasional log or syllable, but the music of the language is crystal clear, with the rhythm, intonation and expression the best possible evidence of the children's feeling for the words. I asked them what they would remember most and the verdict was unanimous: all that cold water in their wellies.
And there was more good news. Earlier this month Martin Pescador was named the winner of the 2012 Spanish Embassy Film Competition, which was open to all Spanish-teaching institutions in the UK: primary, secondary and FE.
Dr Heather Martin is head of modern languages and curriculum coordinator at St Faith's School, Cambridge
Practise Spanish vocabulary with vandersar's interactive cops and robbers board game.
Help pupils to write reviews of their favourite films in Spanish with a scheme of work from QCDA_Resources.