sound pressing shift key

Hi,

Since some time now pressing the shift key at my wireless keyboard produces a strange sound and an upward arrow appears in the upright corner of the screen ?? Not the faintest after which change/update this got into my settings.

Any idea how this can be undone?

Thanks

Hardware Overview:

Model Name: iMac (27-inch, Late 2009)

MacOS: OS X El Capitan 10.11.4

Model Identifier: iMac11,1

Processor Name: Intel Core i7

Processor Speed: 2,8 GHz

Number of Processors: 1

Total Number of Cores: 4

L2 Cache (per Core): 256 KB

L3 Cache: 8 MB

Memory: 12 GB