We’ve actually had ways of observing neural signals for quite some time. In order to identify the regions of the brain requiring surgery for epilepsy, patients get electrodes implanted and spend several weeks in hospital. Various researchers have recruited volunteers from this cohort for neural signal studies. A team recently managed to decode speech from neural signals from such a study!
https://www.ucsf.edu/news/2019/04/414296/synthetic-speech-ge...