A high-performance speech neuroprosthesis Abstract Speech brain–computer interfaces (BCIs) have the potential to restore rapid communication to people with paralysis by decoding neural activity evoked by attempted speech into text 1,2 or sound 3,4 . Early demonstrations, although promising, have not yet achieved accuracies sufficiently high for communication of unconstrained sentences from a large vocabulary 1–7 . Here we demonstrate a speech-to-text BCI that records spiking activity from intra...