'The lower a man's voice, the more powerful and strong he seems to women,' says Judi James. 'In contrast, a squeaky voice indicates childishness.'
When a man gets turned on, normally his voice will go down in pitch and sound deeper, along with his breathing which also gets deeper.
'This is why men with husky voices are seen as sexy,' says Judi. 'The low voice mimics a sexual turn-on.'
A need for speed?The rhythm of a man's speech is also important in working out whether he's sexy or not. 'A rapid, staccato way of talking is a bit like a man who has an uncoordinated walk,' says Judi. 'You just can't imagine that they'll be any good in bed, when a good rhythm is really important.'
And if a man keeps tripping over his words and looks as if he has a blue light flashing over his head all the time, then 'it's a sign of someone who could have a problem with premature ejaculation,' says Judi.
So what should we be looking for as women? Judi suggests: 'It all depends on what you want from a man in the bedroom, but someone who talks with great energy and passion is likely to transfer that to how he performs under the duvet.'