One of my friends - a sound designer and Irish musician - who grew up in Ireland and has a very heavy accent took me to a bar one evening after we did a show and proceeded to pour Irish whisky into me and instruct me in the finer arts of cursing in Gaelic. By the end of the evening I had become quite proficient. Unfortunately the lessons, and the effects, of the whiskey faded.

(This friend is, I swear, a Leprechaun - he is small and for a long time I never saw him eat anything but oranges and drink only Sierra Nevada Pale Ale. And he did the most magical sound design I've ever heard for a wondrous stage production of the not-Irish, but sorta close, Under Milk Wood.)

Another friend and his wife similarly poured single malts into me as they tried to introduce me to new women after my divorce and to, simultaneously, teach me to curse like a proper Glasgow dock worker. Again I became proficient (in cursing, not so much in meeting new women) but that, like my Gaelic, quickly faded.