I thought it was common knowledge that it makes you feel like you could speak a foreign language better. I don't think it's that obvious that the improvement would be objective or that others around you would feel the same way about you.

(And of course there's a Ballmer peak in any case.)

Amusingly, the study found the exact opposite!

  Participants who consumed alcohol had significantly better observer-ratings for their Dutch language, specifically better pronunciation, compared with those who did not consume alcohol. However, alcohol had no effect on self-ratings of Dutch language skills.
https://journals.sagepub.com/doi/10.1177/0269881117735687