The idea behind this quote is that while England and America share the same language, they have significant cultural and linguistic differences that can lead to misunderstandings and miscommunications. Shaw's statement humorously highlights the fact that even though English is spoken in both countries, the nuances, idioms, and colloquial expressions can vary greatly, leading to potential confusion.
It's worth noting that while this quote is often repeated and attributed to Shaw, there is no concrete evidence to confirm that he was the original source. It is possible that the phrase emerged as a popular saying or joke that was widely circulated and eventually became associated with Shaw.
Regardless of its precise origins, the quote "England and America are two countries divided by a common language" has become a well-known and often-used expression to describe the linguistic and cultural differences between these two nations.