Anyone unfortunate enough to have experienced laryngitis knows how unpleasant a condition it is. But apart from the physical side of the illness, there is the whole emotional discomfort that goes with losing control over one's primary form of communication.

"Our voices are central to who we are and central to how we express ourselves," Miriam Gallagher says. "If the voice starts malfunctioning or stops functioning altogether people feel immense frustration because their voice has let them down, but also a major loss of control. "Until you try communicating without your voice you don't realise how central it is to everything you do."

Teachers, preachers and actors make up the bulk of the patients Gallagher sees with voice-related problems. The goods news, she says, is that most problems can be cured with tender loving care and a programme of vocal rehabilitation exercises.

"Anyone who is experiencing persistent loss of voice or continual soreness or huskiness should have the condition checked out by a medical practitioner to begin with," she says. "Normally my referrals come from ear, nose and throat specialists and it's important that people see them to rule out any underlying problem. For example, it could be that the tonsils are causing the problem.

"Once someone is sent to me I will assess how serious the problem is and devise a programme to suit the person's particular needs.

"Many of the people I see have job-related voice problems. It is very easy to abuse your voice in certain occupations and teaching is one of them. Voices have to be raised to get order or to be heard above noise and this means people pushing their voices and forcing them out of their natural range. "We all have a band within which our voices function best; if we continually push them outside their limits then it shows up initially as some sort of strain - such as soreness or huskiness - and can eventually go on to complete voice loss," she says.

Gallagher has been treating adults and children with voice and language problems for more than 30 years; in addition to her therapy work she is a screenwriter, playwright and actor so she knows all about being dependent on her voice to work.

"Actors are normally taught how to care for their voices and how to project their voices to fill a large space. Unfortunately most teachers don't seem to get voice care training and it's their voices that take the main strain in their job.

"In my experience teachers are their own worst enemies - by which I mean they tend to be very giving people who are overly conscientious and they don't want to take time off for something they consider to be trivial like a sore throat.

"So they keep going until eventually something gives and they end up with a far worse problem that takes weeks or months to sort out rather than a few days if it had been dealt with at the outset. "I think teachers should act at the first signs of strain. If they do, more serious problems, such as vocal nodules, can be prevented."

Gallagher concedes her advice might not be popular with principals. "I know it's a problem if a teacher is out sick, but I do think the educational establishment should be more understanding of voice problems because of their potential to become very serious, " she says.

"In my experience teachers can be victimised in the workplace for taking time off with a voice problem and there seems to be a lack of understanding of the fact that people have to stay out of school and not talk if the treatment is to work." Voices used at the wrong pitch and wrong volume over a long period of time will inevitably become damaged; the damage can be hastened by other factors, such as stress or working in an excessively dry environment: chalk dust and smoke are particular culprits.

Those visiting Gallagher for treatment are normally given different types of exercises. For example, some patients may need to improve the resonance of their voices or their breath control, while others need to learn to relax the muscles of the head and neck.

In addition Gallagher looks at ways in which they can use their voices less. For example, she recently ran a course for swimming teachers and got them to use whistles instead of raising their voices.

"I suggest to teachers that they learn to gesture more and to go down to a child instead of shouting to them. I also suggest that they try to have a part of their day that is talk-free, even for a few hours, and to always remember when they are using their voices to use them at the pitch and volume that's right for them. "That goes for talking and singing. I often get teachers who are teaching singing and they push their voices out of their natural range and start a process of irritation which gets progressively worse over time if they keep doing it. If your voice is even slightly hoarse, don't sing. "I also remind people that their voice wakes up two hours after the rest of their body, so it certainly shouldn't be strained first thing in the morning. "Some people have an instinct about protecting their voice, others need to learn it. There's a name for it - vocal hygiene - and it's something that should be taught as part of every teacher-training course."

Gallagher doesn't only treat strain-related problems. With children she often deals with problems of pronunciation, articulation or fluency, while with adults she may treat the voice implications of conditions such as Parkinson's Disease or a stroke.

Parents are often concerned about the pace and way in which their children start talking. With this in mind, Gallagher has written a simple guide for parents which goes through the various stages and problems which can be encountered.

Miriam Gallagher's guide for parents is called Let's Help Our Children Talk and is available in libraries around the State.