German seems extremely hard
I always wonder where that sentiment comes from. Sure, the Grammar is a bit more complex than in English, but afaik it’s still considerably simpler than say Polish.
Plus,they’re fairly closely related, given that they’re both Germanic languages. The writing system is the same, German spelling actually makes sense most of the time, etc. Sure, English imported lots of vocabulary from Romanic languages that German does not have, but learning vocabulary is imho one of the easier aspect of language learning.
Consequently, the FSI classifies German as a category II language, ranging from I (including i.e. Dutch) to IV (which contains Chinese, Japanese, Korean and Arabic), I being the easiest and IV the hardest.
The Chinese writing system alone is enough to discourage people from learning the language up to a fluent level…
AFAIK part of the problem is that the people who don’t drink alcohol include those who no longer drink any, but used to, i.e. recovering alcoholics or people with other health issues.
For any drug but alcohol, studies wouldn’t mix previous consumers in with those who never consumed any of it, but here, afaik, funding from booze companies complicates the situation.