Hints on Pronunciation for Foreigners (Unknown)

I don't know who wrote this delightful poem. Through Google, it seems the options are Unknown, TSW, or George Bernard Shaw. So, that narrows it down.

What I think is kind-of grand in this poem is how it brings out and really emphasizes the non-standard-ness of English (kinda like that word I just used. Hee!). This poem is most definitely only for strong English speakers. And even as a native speaker I still could not read this poem fluidly. Whoever wrote this chose brilliantly for the word pairs. I always stumble here: "A moth is not a moth in mother,/Nor both in bother, broth in brother" because seriously, bother? both? "both"-er!

Favorite line: "A dreadful language? Man alive,/I'd mastered it when I was five!"