Two Welsh sisters have been given the gift of speech after they were robbed of their voice by a rare condition.
Kirstie and Catherine Fields from Llanelli are thought to be the only people in the world who suffer from the neurological condition, named ‘Fields Condition’ after them.
As well as rendering them unable to speak, it has paralysed them and often leaves them in great pain.
The sisters can experience more than 100 uncontrollable muscle spasms a day. There is no known treatment or cure.
But new electronic communication machines have now given them a voice - although the devices cannot speak Welsh, the girls' first language.
Instead they communicate in English, with Kirstie choosing an Australian accent and Catherine selecting an American one, so they can be easily distinguished.
Those closest to Kirstie and Catherine say that despite their condition they are typical teenagers who enjoy getting dressed up, partying with friends - and even getting a tattoo each.
Tonight, in a programme to be shown on S4C, they speak of their condition as they mark their 18th birthdays.
It's unclear what the future holds for the sisters, but those closest to them say it hasn’t robbed them of their spirit, intelligence or humour.
O'r Galon: Fy Chwaer a Fi is on S4C on Wednesday, September 12 at 9pm.