How useful English language actually is? (upper-class, home, school)

[paparaciii]

When we read characterizations and statistics about English language, it allways gets such labels as "world's lingua franca", "most widely spoken language" etc.
But as we know, English has a huge amount of dialects and accents. So I was wondering what is the percentage of so called English speakers that can understand each other if they speak just the same way they speak in their home town or village, I mean if they speak the language they picked up from their parents and friends, not the language they learned at school.
Let's say, if an avarage American guy would travel all around English speaking countries, in how many of them he would feel comfortable in terms of intelligibility of locals?

[boardmanite]

As an average American guy, here are a few of the "Englishes" I had a hard time understanding:

Scottish
South African
Guyanese (Guyanan???)
Southern US

[ara^bess]

What an interesting question! When my mom came to the southern portion of the USA as a war bride, she said even after speaking fluent English in Germany, she had no idea half of what my dad's family was saying to her when she first arrived. She is now a full southern speaking woman....but she said it took time.

[Chava61]

I have had a hard time understanding some Scottish people as well as people speaking a Cockney (lower working class in London) accent.

[mayonaise]

Jamaican English is, in my opinion, the most difficult for me to understand.

Indian English and Kenyan English have a pluralized form for words like "money" and "furniture," that seems odd to the American or British ear.

But such is the case for all global languages. For example, I thought I spoke fluent Spanish because I could hold an extended conversation with middle- and upper-classed people from Mexico City. Lo and behold, I was shocked when my plane landed in Buenos Aires, and I couldn't understand a word of Porteño Spanish.

[Iconographer]

To your original question of how useful it is: I would say immensely so.

[EricNorthman]

Originally Posted by mayonaise

Jamaican English is, in my opinion, the most difficult for me to understand.

Indian English and Kenyan English have a pluralized form for words like "money" and "furniture," that seems odd to the American or British ear.

But such is the case for all global languages. For example, I thought I spoke fluent Spanish because I could hold an extended conversation with middle- and upper-classed people from Mexico City. Lo and behold, I was shocked when my plane landed in Buenos Aires, and I couldn't understand a word of Porteño Spanish.

I want to second Jamaican English. It can be very difficult to understand unless they speak quite slowly.

[pgm123]

All this is true, but I've found communication to be no problem provided that both sides were actively trying to make the other understood. There are accents even in America that are difficult, but I know Brazilians who say there are accents in Brazil they can't understand, so that's not so different from anywhere else.

[Tom Lennox 70]

I'd say Jamaican and Nigerian English is the hardest to understand.

Now in terms of people whose first language is not English, the Vietnamese accent is very hard to understand.

[geoking66]

Glaswegian and thick Welsh accents are the toughest for native English speakers. Non-native is anyone's guess.