A team of scientists from the Centre for Innovation in Neuroscience and Technology at the University of Washington is one step closer to mind read, peering into the deepest recesses of the brain to watch words forming.
The finding could one day allow those with severe disabilities to 'speak'.
Using electrodes, the researchers found the area of the brain that is involved in creating the 40 or so sounds that form the English language.
They then discovered that each of these sounds has its own signal which they believe could eventually allow a computer programme to read what people want to say by the power of their thoughts.
Led by Eric Leuthardt, they studied four people who suffered from severe epilepsy who each had 64 electrodes implanted into their heads.
The subjects were asked to make four repeated sounds - 'oo', 'ah', 'eh', and 'ee'.
The team then monitored the Wenicke's and Broca's areas of the brain for signals related to speech formation.
They were then able to pick out the corresponding electrical signals, and while these four signals will not be enough to form sentences, further research could lead to this becoming possible.
"What it shows is that the brain is not the black box that we have philosophically assumed it to be for generations past," the Daily Mail quoted Leuthardt as telling the Sunday Times.
"I'm not going to say that I can fully read someone's mind. I can't. But I have evidence now that it is possible," he added.
Leuthardt also found that the brain generates a signal when people just think about the sounds - but it was very different to when they speak it.
This has led to the implication that doctors could one day read people's private thoughts as well as what they want to say.
And it is hoped the research will one day give people with locked-in syndrome the chance to speak - as currently electrode treatment on the brain can be carried out those that are severely ill.
It could, in principal, also lead to technology that could read the mind without surgery - and even lead forms of communication, which work, only by thought.
The research was published in the Journal of Neural Engineering.