They struggle with not only the sounds (by way of
articulation A) and
contrasts (by way of difference
B)
The sounds you won't hear:
bi-labial soundsA: except for b, p, m and w (the same as English), but lacking secondary articulation (except for stereo typified works like 'buí') and 'feoil' (for glides). The slender varieties are missing exceot when marked by a glide
B: /w'/ as English 'v' and /w/ as English /w/. No broad slender for words beyond pairs learned at school like 'buí' and 'bí' and even here, the b in bí is plain
dental & alveolar soundsA: As Redwolf says above, tendency to lack dentals and even then, to omit the velarisation unless they're they have a type of Americanized speech and that would be just down to accident and not the same as natives anyway; /d'/ and /t'/ nearly always like 'j' and 'ch' in English; 's' and 'sh' are the same as English, the broad s not velarized. The sh in both languages are not easy to distinguish (tho with old people it would be easier as they, even in English have a range of realisations (including a whistle sound!); /r/ and /r'/ are missing, as is the velarisation on the broad r, with only the speakers usual English r here; 'l' and 'n' are missing most of the time, replaced by their dark English versions or a lighter variety, varying as in English (even tho all 4 original l and n sounds can be found in some English dialect, and most people have 3 in some capacity, ex: pill, pull, million, but they don't consider them different)
B: broad and slender only where English maps onto Irish with the nearest equivalent -the rest missing
made mostly with the palateA: Apart from people from the old Ulster Irish area, slender c and g are missing, but even hey don' have the broad, or have a more English-like broad form or vary them word by word depending on context; /x'/ is gone to it's reward, totally (most probably don't even know it exists) yet they can make it in English (...); /j/ exists, again because it is in English; slender /ng'/ doesn't get much of a look-in
B: /c'/ and /g'/ only contrasted by accident for people in or near Ulster; no contrast of /x'/ and /j/ to their broad sounds below; maybe a /ng'/ to broad contrast, depending on how apparent the connection is. Young people in Ireland often have variable ngs in English
velar/uvular soundsA: plain or maybe broad /k/ and /g/. Maybe a velar 'ch' now and again. Usually, ch is uvular to me and gh probably is too. Ch and gh usually replaced by k and g from English
B: No real contrast here to anything
glottal -'h', yes!
So, basically, to give you a short answer, it's almost ANY sound not in English, BOTH in terms of articulation and ESPECIALLY in contrast. And since people are not told the sounds are different (look on the net, most 'pronunciation guides' say Irish and English are much the same), they don't know to say them right
As an example, look at the top results for 'how to pronounce Irish':
http://angaelmagazine.com/pronunciation/consonants.htm -says there is a difference, and gets a number of them, but the .wav format is not browser friendly, and many will ignore him for being an American
http://www.standingstones.com/gaelpron.html#ConsIrish has fewer consonants than English. As you can see, most of them are pronounced very much like English. Actually, for the purpose of simplicity I am leaving out a few subtle differences. Like the whole thing
http://www.smo.uhi.ac.uk/gaeilge/donnch ... ishsp.htmlSpoken Irish has only a few sounds not found in some dialect of English. You'd think SMO would be more on the ball and they even go on to contradict themselves by saying further on:
all Irish consonants come in two flavors, called “broad” and “slender”. Basically, broad consonants are pronounced with a “-w” off-glide, and slender consonants are pronounced with a “-y” off-glide. which is not true (if so, both languages would sound different to how they are and more like each other)
http://en.wikibooks.org/wiki/Irish/PronunciationStarts off with mentioning
the complete difference between pronunciations in Irish and English and then later talks about broad and slender before confusing the issue with
In most cases, the difference between the broad and slender pronunciation is subtle and then giving the old reliables d/j, t/ch etc
http://www.omniglot.com/writing/irish.htmLists the differences (but no /x'/!) and misses the 3rd existent l and n sounds before messing it all up by having a recording of that Cavan bollox with the language software to muddle it all up again