When Stephen Hawking wanted to speak, he chose letters and words from a synthesiser screen controlled by twitches of a muscle in his cheek.

But the painstaking process the cosmologist used might soon be bound for the dustbin. With a radical new approach, doctors have found a way to extract a person’s speech directly from their brain.

The breakthrough is the first to demonstrate how a person’s intention to say specific words can be gleaned from brain signals and turned into text fast enough to keep pace with natural conversation.