As far as accents, my English mom said that the Welsh accent is so strong that if you spent any time with them, you would end up with their accent. When I went to Wales as a little girl, I didn't start talking like my Aunt (by marriage)--mostly because I couldn't understand a darned word she was saying.
I often have trouble being understood ordering an almond croissant. I don’t know how to correctly pronounce ‘almond’, I think I pronounce it with the ‘L’ silent, but even when I say ‘al-mond’ they still don’t understand me.
I usually take British Airways when travelling to Europe (which airline I do recommend), and some of the stew staff speak with such strong Cockney accent that I don’t understand them when they propose chicken or beef, or ask if i want ice with my tomaHto juice.