We don't know much about the Fremen.
4 seconds sound clip from the Dune (1984) movie soundboard.
You can hear this line at 00:24:42 in the Blu-ray version of the movie.
Quote context
[...]
- Is it true that the sand can blow at 700 km per hour?
- It can render flesh into dust in minutes.
- And these dry winds can also generate tremendous amounts of static electricity in the atmosphere.
- Our body shields won't have enough power to operate in the open air on Arrakis.
- How do the Fremen survive there?
- We don't know much about the Fremen.
- They live in the deep desert, some of them in the cities.
- They have blue-within-blue eyes.
- Saturation of the blood by the spice melange.
- Could the spice affect us in other ways?
[...]