I understand. I forgot to ask you if you were a native English or German native speaker.
I am a French native speaker. Born and raised in Paris. When I started to work internationally, my French was the typical Parisian accented one. When I listen to me speaking anything, I hear my French accent.
Each time I return to France, I have some people asking me how come I know French so well. I surprise them when I tell I am French, born and raised. Somehow, over the years of expatriation, the lack of speaking French, I am guessing my accent is no longer current; this is most likely why French people that don't know better think I am Canadian. They have clearly never heard a French speaking Canadian.
Another dead give away is my first name. From the 50's. Also, I am using expressions which are no longer used today. When you don't live in the country, you don't stay current. Typical. The first names are usually a good indication of the age of a person.