German in the Soviet era...
How different was German spoken in East Germany from that spoken in West Germany toward the end of the Soviet era?
Not much. Maybe a few words that were only used in East Germany, but in not the west and the other way around. Kaufhalle (east) vs. Supermarkt (west) for example.
And of course there are a lot of regional dialects, but those have always existed.
It was the same language but different dialects,
Examples: English-Supermarket West German-Supermarkt East German-Kaufhaus
English-Orange (fruit) West German-Orange East German-Apfelsine
Hope this helped!
In West Germany had already established many Anglicisms, but in East Germany of course not.
MoritzS.S. is right, even though you also have to consider that there is not only one dialect in East Germany. But listening to an East-German I can better hear where he is from than listening to a West-German. Average!
If you are interested, here some vocabulary concerning this theme:
East Germany - Ostdeutschland, die DDR (Deutsche "demokratische" Republik - German democratic republic)
West Germany - Westdeutschland, die Bundesrepublik (federal republik)
East German (person) - Ostdeutscher, inf Ossi
West German (person) - Westdeutscher, inf Wessi
the reunification - die Wiedervereinigung
die Mauer - the wall (through Berlin)
der Mauerfall - the falling of the wall in Berlin or rather the opening of the border on 9th November 1989
Todesstreifen - streak along the east side border. Everyone who went there was to be shot by DDR-soldiers
Mauertoter - person who died while trying to cross the border (from east to west)
Tag der deutschen Einheit (17.6.) - West German holiday to remember the wish of one state, celebrated 1954-1989. The date refers to the Arbeiteraufstand/Volksaufstand on 17th June 1953 in East Germany which was shot down by Soviet tanks and soldiers. (for more information for ex. https://en.wikipedia.org/wiki/Uprising_of_1953_in_East_Germany)
Tag der Deutschen Einheit (3.10.) - Holiday since 1990 to remember the reunification. On 3rd October 1990 the agreements about the reunification came into operation. This date was chosen becourse it was far away enough from any other holiday.
Ostalgie - nostalgia referring East German everyday life (nostalgia=Nostalgie)
die Wende - general: the turn; here: the period 1989-1990 which caused the reunification
Trabi - the car produced and selled in the DDR
die Neuen Länder - the five states of Germany that were the DDR until 1990 (state=(Bundes)Land)
I can add some more if you want.