Sprachgefühl

 Was what Michael, my lovely manager at Longman said when I passed the test to become a lexicographer (yes, there was a test - bet some of you would love to take it)

He said I had "Very good Sprachgefühl" which I took as a big compliment, but I soon realised he was right and I should have known anyway.

The way we use it in English is 'feeling for language', an innate or trained ability to know what is linguistically appropriate in your own language (or another). It will tell you when something is grammatically non-standard, although you should also know whether it is a proud, local and ancient variant or hangover (like "brang" if you are proper Ipswich "where's your homework Kyle?" "I brang it in yesterday")

Your sprachgefühl will also take you through people's word choices and tense choices and often tell you when they are lying or dissimulating. It will show you gloriously apposite phrases to which you give a mental 'chapeau". It makes language richer for you, and it helps you write better dictionaries and, perhaps, blogs.

But also, when your manager says it, sprachgefühl will make you start thinking about the register messages of borrowing a foreign word in your professional work. And from which languages.

My current league table is that French is on the lowest rung: mise-en-scene; mauvais foi, etc.

Italian is, I feel a rung above: chiaroscuro; coloratura; littoral. Maybe it just sounds nicer 

But when you can get your tongue around your Weltschmerz and Realpolitik or use Sprachgefühl completely appropriately, I think you are top dog.