What is the difference between dearg and ruadh here? I always thought dreag was used for 'red'? Thanks!
"Nach eil falt dearg ort?" would imply do you have red (dyed) hair. Ruadh is used for a more brown shade of red.
It's different types of red that we don't usually distinguish in English.
"Dearg" would be the deep red of, e.g. blood. "Ruadh" is the more rust-colour red of (natural) red hair, animal fur, etc.