YOU SAID:
I impressed my American coworker by speaking German to a German.
INTO JAPANESE
私はドイツ人にドイツ語を話して、アメリカ人の同僚に感銘を与えました。
BACK INTO ENGLISH
I spoke German to Germans and impressed my American colleagues.
INTO JAPANESE
私はドイツ人とドイツ語を話し、アメリカ人の同僚に感銘を与えました。
BACK INTO ENGLISH
I speak German with Germans and have impressed my American colleagues.
INTO JAPANESE
私はドイツ人とドイツ語を話し、アメリカ人の同僚に感銘を与えてきました.
BACK INTO ENGLISH
I speak German with Germans and have impressed my American colleagues.
You've done this before, haven't you.