A San Francisco startup called The Subvocal Company says it has raised $1.3 million to develop smart glasses that allow users to type without speaking aloud or touching a keyboard.

The glasses use sensors to detect tiny facial muscle movements when a person silently forms words. Artificial intelligence then converts those movements into text, allowing users to write messages or communicate with a computer.

The company claims its technology can process more than 200 words per minute. The glasses are still under development, and the claimed speed has not yet been independently verified.