Although the American term "Internship" is starting to appear over here in the UK, it is more often called "work placement" or "work experience". Would Duolingo accept those terms?
I am British, and I would say that in a sentence like this with no context, the word "work" is needed before "placement". As I said before, we talk of "work placements" and "work experience". But I agree that "internship" sounds unusual in a British context.
I am aware that Duo is a computer Program so its English database should be amended so that "Lasts FOR Twelve Months": "Lasts for one Year" "Takes Twelve Month"s "Takes one Year" should all be correct answers to this particular question. at least from languages going to English The German language translations may be more limited and succinct, that is the impression that I have of Duo's German usage, the briefest answer is the invariable the best.
Not in British English. Here, "the practical" tends to refer, for example, to those parts of science courses (in school, college or university) which involve experiments. As I said before, for periods of training where school pupils or college students spend some weeks in a workplace, we would say, "work experience" or "work placement".