`Say those lines much faster, but make it sound like you're talking very slowly."

"Put more twinkling smile into the words `driver's air bag'."

"Say `terms and conditions apply' as if it was one syllable."

A voice-over artist gets these kind of requests all the time.

When the advertising agency's creative team brings their concept to completion, a decision is made about what voice they want to use. Once they decide, they make a phone call to book the voice artist. As a result, the voice-over artist's "typical" week begins not knowing what's going to happen. The buzzword to describe this perennial state of supplicant readiness is "available" - as in "Check Roger's availability". (When I was young and innocent "available" meant "unemployed".) That's why the voice-over artist is so grateful for the mobile phone. It permits us to leave our houses, be seen in the sunlight or use the toilet and all the while still be waiting for the phone to ring.

Thankfully, once you are established the phone actually does ring a few times each week and you get the call to appear in a studio. You walk in not knowing anything and in a matter of minutes you're a gnarly pirate raving about fish fingers, or a kooky gangster conspiring about a chocolate bar, or just a really friendly trustworthy guy going on about pensions. They call us voice-over people "artists", but I really believe that a lot of the writers in advertising are as well (despite the occasional business suit). Given 60 seconds or less to work in, they are supposed to be funnier than most comedians, more observant than a satirist and more succinct than a poet. The very best ads create a stir in the mind and dare I say it, transcend their immediate corporate intention.

Take that "Whassssuuuup?" ad. It's a wonderfully poignant comic haiku on friendship. That's where art takes over and the business falls away. Sure there are bad ads. But bad ads usually stem from an over-cautious client who insists on including two phone numbers, and eight price lists, or toning down the vocal excitement, which means cutting out what makes the ad captivating in the first place. That's where the art stops and the business takes over.

Most voice-over artists are actors. Some mostly still work in theatre, with a few jobs doing voice-overs thrown in; some get so much voice-over work that they pretty much have to shelve their acting. I got my break thanks to Noel Storey, one of the best sound engineers in the business. With his endorsement my career in voice-overs really took off. I am a playwright who began writing plays for Graffiti Theatre Company in Cork in the early 1980s. Since then I have written about one play a year for various companies. I have my own digital recording studio. Over the past few months I have produced music and sound effects for 2FM, comedy sketches for Rattlebag on RTE Radio 1 and music soundscapes for Barrabas Theatre Company.

A couple of years ago I established Crazy Dog Audio Theatre, which has so far released two productions of "Bill Lizard" comedy adventures on CD. They are getting a lot of airplay around the US. There are more Crazy Dog Audio Theatre projects in development. Because of all the work, I get up every day before 5 a.m. in order to write for a few hours. At the moment the voice actors with Crazy Dog Audio Theatre and I are busy rehearsing Invasion From Planet Vampire, a camp outerspace comedy which is going to be performed on RTE Radio 1 this Saturday, live from the Octocon science-fiction convention.

I love talking in funny voices and getting paid for it. It's fun, and it leaves time to write and produce. Though an accountant has assured me that, by his sensible standards, I must surely be insane.

Invasion from Planet Vampire goes out on RTE Radio 1 this Saturday evening at 7 p.m.