"Kann nicht sprechen Deutsch"
The people of Ingolstadt, Germany speak German as their primary language.
In Germany, people speak German.
They might speak it if they have studied the language elsewhere but if generalizing then no, swedes don't speak German.
She speaks German and English
Australian people speak Australian English. German is spoken in Austria. Sometimes these two countries are confused. However, there is a small but significant population of Germans living in Australia.
In Germany you speak usually the German language.
Does he speak German = Spricht er Deutsch
No she doesn't speak German.
How do you speak German = Wie spricht man Deutsch
They are German so they speak German to each other.
People in Vienna speak Viennese German.
No, sprechen means speak in German.
Does he speak German = Spricht er Deutsch
There are gnomes that speak German fluently because they are german. Or they simply studied it.
"Do you speak in German" is "Sprechen Sie Deutsch?" (formal) or "Sprichst du Deutsch?" (informal) in German.
German is not the official language in Estonia, but some Estonians surely know how to speak German.
It would be most unusual for a German not to be able to speak German. I therefore answer 99.99% of Germans speak German. The reasoning :- there is a very small percentage of people who have speech impediments that rends it impossible for them to speak at all.