Additionally, players claim that Nimble Fingers speeds up 'weapon operation', some say as much as +100%. However, just what 'weapon operation' entails or how this could be confirmed is still unknown.
This skill can be a very good replacement for Loader (which takes an equipment slot). The only tradeoff is that it's not as fast as Loader when dealing with weapons that have large magazines, such as Machine Guns. On the other hand, Initiative boosts may be able to negate this tradeoff.
Phalanges are the correct word for fingers.(Source)
The French name, "Doigts-Agiles", isn't much different and can be roughly translated as "agile fingers".