I have often had it remarked to me that the UK has such a wide variety of accents and dialects it seems to many Polish natives that many of us don't speak English at all, but something very similar, changed sufficiently to represent be called a whole new language altogether. Many people I've met in Poland say this is true of American English speakers as well. Of course, I'm able to understand most UK regional accents, but I can't say I can understand them all with ease; I particularly struggle with northern accents, and a lot of my Polish friends have told me, the Scottish accent is entirely impossible for them to comprehend.
When I came to Poland I was curious if the same would apply; if, as I gradually became able to understand Polish more and more, whether regional accents, in a country that has a much greater geographical spread than my homeland, would present similar linguistic hurdles. The answer, in short, is no; but, not a 'that's-the-end-of-it' no.
Granted, it took me a while to notice regional accents and linguistic nuance, but once I had clocked them - usually at the guidance of my Polish friends – I started to notice them more and more.
Poland is usually separated into four major dialectical divisions. Over the last two hundred years many aspects of each of these have been assimilated with each other however, meaning that the Polish language overall has become much more homogeneous. The dialects currently cited by most, from north to south, are the Greater Polish, Masovian, Lesser Polish, and the Silesian.
The język śląski (Upper Silesian Language) is still officially designated as a separate regional language, but it's status is very tenuous. Official recognition does not necessary signify lingual recognition, and Silesian really is very similar to Polish proper, while there is virtually no change in accent.
The most distinctive and nationally recognised 'separate' dialects belong to the North of Poland, in Mazovia. These are characterised by a distinct dropping of the Polish nasal vowels 'ą' and 'ę' for 'u' and 'a' respectively, and a much heavier use of the y vowel sound, particularly instead of the long 'ee' sounding i.
In contrast, the less distinguishable dialect of South Poland - the Dialekt Małopolskie (Dialect of Lesser Poland) - is marked by heavy use of the nasal vowel and an elongation of their constituent 'n' or 'm' sounds. In practice the Lesser Polish and Dialekt Wielkopolska (Dialect of Greater Poland) are largely indistinguishable, maybe due to the regions' intersection over the country's major cities.
Some regional languages still survive, particularly in the north, where the język kaszubski (Kaszubski Language) is still relatively prevalent on the coastline towns and regions around Gdańsk. Unfortunately within the język kaszubski the prevalence of sub-dialects (gwara in Polish) is such that many northern simply can't understand the Kaszubian speaking southerners.
When it comes to accents, Poland really doesn't have the same variety as somewhere like the UK. It's very handy when you realise that means you'll be able to understand someone from the southern Slovakian border towns just as much as if they were from Gdańsk. That said, I've heard many people say that the one area with a distinct accent is around the mountain, ski-town, Zakopane in the south. In-fact the people who live there are quite proud of their accent and it's definitely possible to detect that little difference. It must be all that mountain air!
With one last note on dialects though, I'll leave you thinking about one of the greatest linguistic dichotomies gripping Poland today. It has inspired Facebook groups and Twitter followings to rally supporters to either side, but it's really not that glamorous; you're Either from Kraków and say idę na pole (I'm going outside), or from anywhere else in Poland, where it's idę na dwor. Careful though, it's a zealous argument.