It's 9.30 a.m. on a Sunday morning and the car park at Blackrock College in Dublin is full of buses and tanned young language students. They're all tanned. They're wearing pretty much the same gear - designer runners, sweatshirts, jeans, and bright backpacks - but the single most distinctive feature they share is that they all have honey-hued limbs.

After the non-summer we've had, something clicks. Perhaps the reason foreign language students are regularly grumbled about in Ireland is that they remind us forcefully that some other countries get sunshine on a regular basis.

There's a kitchen trolley in the middle of the car park, which is loaded with paper bags containing lunches. It's visited at intervals by students who are waiting to board buses for their Sunday outings. Some buses are going to Kilkenny, others to the Japanese Gardens. Ours is going to Wicklow: Glendalough and Avondale House.

On board are 26 students, most of them Italian or Spanish teenagers between the ages of 13 and 16. But the two youngest, Inigo Andia and Alex Vasiliev, are from Alicante and Moscow respectively. Both are nine. They're sitting together at the front of the bus, behind the driver, investigating the contents of their lunch bags. They start tucking in even before the bus pulls out of the car park. Inigo is wearing a Planet Hollywood Dublin T-shirt and bright yellow runners. Both laces are undone.

All these students are with A.T.C. Language and Travel, which was set up 35 years ago. It handles more than 5,000 foreign language students each year, most of whom stay for three weeks. The routine is pretty much like life in the Gaeltacht: staying with host families, language classes in the mornings, games and activities in the afternoon, and outings like this one at the weekend.

For a bus that is mainly occupied by teenagers, it is astonishingly quiet on the journey out towards Wicklow and the hazy outline of the Sugarloaf. There's no singing, very little conversation that rises above a gentle murmur, and nobody is sitting in the seats which are usually the first to be commandeered - at the back.

Aisling Shiels is one of the group leaders supervising the outing. She's sitting up front, opposite the nine-year-olds. As we drive deeper into Wicklow, she points to cows munching away in the nearby pastoral fields. "What's the English word for those animals, Inigo?" she asks. He doesn't know. "Cows," Aisling says brightly.

"Cows!" Inigo squeals. "At McDonald's, they kill the cow and eat the cow. Yum yum! I love McDonald's!" Inigo talks non-stop for several miles, a restless little bundle of energy. Spain is the greatest country in the world. Madrid is much bigger than Dublin. But when I ask if he misses home and his family, he clamps his mouth shut and ignores the question.

Ten minutes later, Aisling asks the same question. Inigo leaps to his unlaced feet, grabs what remains of his lunch and scampers down the back of the bus. "I'm going to lie down back here and go to sleep," he shouts. "I'm very tired from all that talking."

The sun makes an appearance when we reach the Dargle River. A dozen motorbikes pass us out. All the lads press themselves against the glass and whoop as the bikes whizz by. The bus goes through a tree-canopied tunnel and emerges in forestland. Some of the students take pictures through the window. At Laragh, the top of a round tower can be seen through the trees. More pictures.

Like all the Italians on the bus, Ilaria Carsillo (14) is from Pescara, in Abruzzo. At Glendalough, Ilaria says that what she likes best, of what she's seen so far in Dublin, are "the things from the little old houses". After a bit of conferring and translation with Rosaria Sannteusanio and Loretta Lattanzi, group leaders for the Italian party, it emerges that Ilaria means the Viking artefacts in the National Museum.

Asked if she feels lonely away from home, Ilaira looks astonished and then laughs at the question. "How can I be lonely when I am here with friends from school and the group leaders?" she answers, before wandering off to join her friends.

"The kids sent postcards home a couple of days after they got here," Rosaria says. "We read them to see how they were feeling. One boy had written `I am not missing you at all. And I am spending all your money'."

There's a short tour of the monastic site at Glendalough, given by a guide. The sun is half out and yet the place still manages to look darkly intimidating; all clotted forest and leaning Celtic crosses, with the lake glinting in and out of view at intervals. The round tower attracts many photo-opportunities, but the guide's commentary is either too fast for the students or as uninteresting as these things usually are when one is a teenager, because not many of them listen to him.

Walking down to the lake, where the remaining lunches are due to be eaten, Alex falls into step with me. His right fist is tightly clenched on a rolled-up five pound note. He has no pockets. His English is rudimentary. "I like all the green here," he says shyly, after a while. "All the trees. Moscow does not look like this."

Is he happy here? Alex looks down at the ground and clenches his little roll of money even tighter.

"In Moscow, I am many. In Ireland, I am only one." Then he breaks into a run and when the rest of us reach the lake, he's at the water's edge, looking at stones with his back to us all.

Dalila Ficcaglia (16) misses "the pizzas and pasta. But nothing else!" It is her first time in Ireland. "We studied a chapter from the Ulysses in school. James Joyce. The characters are very strange." What does she like best about Dublin? "Grafton Street," is her quickfire answer. "All the shops! I love to shop."

A small riot breaks out on the grass. One of the boys is enclosed in a cocoon of cassette tape. Everyone is giggling. "A violent boy broke the music," he tells us, showing the cracked and empty cassette. "It was Metallica."

Most of the Spanish students are from Barcelona. Marta Lujan (13) has very little English but she is clear in communicating the fact that she is not one bit lonely. Whatever the Spanish for having a whale of a time is, that's what she means.

Her compatriot, Carlos Jimenez, is also 13, also with basic English. The group leader translates our conversation. "Carlos says he is very homesick. He is phoning home every day. He is counting the days left in Ireland."

Back on the bus, we're heading for the Vale of Clara. Ferns collapse on the verges. The trees are barked with moss. There are a few lone French flags hanging from the tops of telegraph poles. The bicycle clipped out of a hedge in Rathdrum is already beginning to look overgrown.

At Avondale House, the hit of the guided tour is the nannny's room. The guide shows off a big wooden medicine chest that the Parnell nanny used to tend to the children's ailments. "There's a little drawer here, look." Everyone cranes over the barrier. "She kept cocaine here. She gave a pinch of it to calm down the children when they were sick."

There is silence and then, as the students start laughing, those who haven't understood what's been said implore their peers to tell them what the joke is. Within a minute, the room is rocking. When these language students go home, they mightn't remember who Charles Stewart Parnell was, but they'll certainly remember that his nanny gave him coke to calm him down when he was a baby.