39 postcards & 2 letters written in German from Frederike Schafranik together with 12 postcards written by Gretl Gerhert? 9 in English, 3 in German.
53 items in total.
All 41 items written by Frederike Schafranik (nee Meisel) (1862-1942) to Johannes (Hans, later John) Schafranik (Shack) (b1907) are in German.
Most correspondence is posted from Frederike Schafranik, Villa Ella, Badgastein, Austria to her son Dr Johannes Schafranik to various addresses including: 19, Hungerberg Strasse, 6, Vienna, 19 Scheibeng, 3, Vienna, 4, Pressgasse, 28, Vienna, 1 Randolph Road, London W9, Hotel Pax, Paris, etc, etc.

The batch of 12 (9 English, 3 German) written postcards are again all to Johannes Schafranik, written mostly 1930-1932 to various addresses in Vienna, Cologne, London, etc. very difficult to read the name of the sender. Closest guess would be Gretl Gerhert (see close up scans).
Having briefly cross referenced names/addresses/dates with public information, and please note this is not an expert opinion, my findings are thus.
Gabriel Schafranik (1864-1927) married Henriette (nee Meisel) (1866-1904) then married Frederike (nee Meisel) (1862-1942). Sadly it appears Frederike Schafranik died in a concentration camp 23rd Sep 1942.
Dr Johannes Shafranik settled in the UK, London then Birmingham/Sutton Coldfield and anglicised his name to John Shack and was married to Dr Margaret Shack.
The content of the earlier period English postcards, whilst difficult to read, I think the gist of them is the writer is bemoaning the weather and her health ailments in most.
The contents of all the Austrian batch (41) written in German is unknown but no doubt an important piece of social history given the run up to the 2nd world war and the unfortunate nature of Frederike’s passing.