Seven Ages Of The Voice (Radio 6, 4.30pm) may not contain many startling scientific revelations, but it does break down the changes in the way we speak into seven handy little categories, and uses lots of nice interviews to make its points. The programme intends simply to explain the way the human voice changes, the way we learn to use it, and the way we express ourselves quite apart from the words we use. Where better to do this than on the radio, where we have to listen closely to the voices of the contributors because there is not anything else. In the first episode, presenter Laura Spicer uses clips from babies, toddlers, seven-year-olds and teenagers from all over the world. Sometimes these are upsetting - the sound of a lonely new-born howling; sometimes adorable, as when a toddler explains why cats do not eat mud; and sometimes really funny, as when a teenage boy grunts down the telephone at his friend. It is also full of the quirky, curious little facts which good radio features can present so well, such as the suggestion that all babies all over the world say 'dadadada' because that is the noise they make when they push away their mother's nipple, or the teat of a bottle. I use the Internet every day (who does not, these days) but only because I have to, and not because I think it is the all-powerful, all-liberating, all-knowing road to the future or any other such nonsense. It is handy e-mailing people, and sometimes one can pick up a few interesting facts. But a lot of it, let us be perfectly honest, is inaccurate, unreliable, irrelevant, self-indulgent, badly written and impossible to find except by accident. How the Internet came about is still a tale worth telling, and in another excellent BBC documentary (is that a tautology?) Inside The Internet (Pearl, 8.30pm) tonight, we hear it told well, and in some detail. The whole thing began, apparently, when the Russians launched Sputnik in 1957 and the American government became so anxious about losing the technology war that they quickly ordered the military to start using computers to communicate internally. Then an AT & T employee who clearly had too much time on his hands, or just remarkable initiative, invented UNIX even though no-one had asked him to. College computer systems began to get connected, then the military. It looked as if the Americans were winning the technology war in one area at least, until in 1984, KREMVAX appeared. The Russians were on-line! Except that they weren't. It was just a mischievous European researcher playing a practical joke. Then Tim Berners-Lee started dreaming about creating a virtual talking shop which became the World Wide Web as we know it today: filled with ads, littered with junk, and often extremely frustrating to look at. Not a million miles away from television, when you come to think of it.