Tourists coming to Ireland often complain that even though they expect most people to be native English speakers, they often find out to their horror that they can't understand one word being spoken. Yes, Irish people speak English; but it's an Irish sort of English, which can take some getting used to. So, if you are going to have any chance making your way round the island, a few helpful tips on the local vocabulary would be helpful.
Greetings tend to vary from place to place. In the southeast it might be Well, boy; while up north you might be greeted with 'Bout ye1. In parts of Dublin it could be Howyiz, while in Cork you might be confronted with Howsitgoin' boy? A more rural equivalent is How's she cuttin'? A suitable reply is Grand altogether if you are in good form, or Survivin' if not.
Irish people like having fun, and have many words to describe this national propensity. Even 'fun' has its own word - the crack2. If something is great crack, then it's likely to be tremendously enjoyable. The word gas is often used to mean hilarious, but if you are called a 'gas man' and what you have just said or done was incredibly stupid, be aware that someone might just be piling on the sarcasm nice and thick. If you hear that someone is acting the maggot, or is messin'3 or trick-acting then they are in a mischievous mood designed to get a laugh from others, often at the expense of some poor unfortunate. A slagging match is where two evenly-matched opponents start to insult each other in a good-natured way. Someone who is having a great time (often while others are not) is said to be having the life of Reilly.
Drunkenness, for some strange reason, has a rich lexicon in Ireland. You can be ossified, fluthered, in the horrors, langers, locked, paralytic, plastered, scuttered, stocious, twisted and sozzled, to name but a few - so many different words to mean the same thing.
Irrespective of your social or geographical upbringing, there is probably a special name for you. Fellas4 is used to denote males, while wans5 refer to females. The mot or the aul' doll is your girlfriend, and a good-looking person of the opposite sex might be a regarded as a fine half. A culchie or a muck savage is a term of endearment reserved by townspeople for country folk. Dubliners are called Jackeens. Irish people with an affinity for the island across the water are called West Brits. A real lawdy daw is someone with a posh accent. An overtly religious person is in danger of being called a Holy Joe. A father is often referred affectionately by his children as de aul' fella. The moniker hoor is often used in many different contexts. A 'right hoor' is a deeply dislikeable character, whereas a 'cute hoor' is the type of person who displays a strong degree of craftiness - these people often end up running the country. People who perform remarkable acts of idiocy might be called eejits or gobshites.
Irish people are known to talk. A lot. To blather or rabbit on about something is to waffle at length. To talk ninety6 to the dozen is to talk so fast nobody has a clue what you are saying. If you don't have a clue what you're talking about, then you're talking shite. The word blarney, to denote flattery, is not in common usage.
Good and Bad
Getting it Right
If it meets expectations it's the business, and you will be congratulated with comments like fair deuce or fair play to you. If something is really good you might hear someone exclaim deadly!
Getting it Wrong
To make a right bags or a right hames of something is to get it spectacularly wrong or to mess it up. To invite massive embarrassment make a holy show of oneself. If something is very bad it's wojus or brutal. If a Dubliner agrees with you that it's really bad he might say 'Hate tha' 7'. The expression 'What are you like?' is synonymous with 'I can't believe you are so stupid'.
Other Miscellaneous Phrases
Wayward children are never naughty - they are bold.
To be tired or broken down is to be banjaxed or knackered.
To procrastinate or delay something is to put it on the long finger.
A sub-standard dwelling is called a kip.
If someone is annoying you, they are blaggarding.
To ask someone to be quiet you might say whisht!
A scratcher is a bed and the jacks is a toilet.
To emphasise something the word fierce is often used, as in 'fierce hard' (ie difficult) or 'he has a fierce strong accent'. The words quare8 or awful can also be used to denote emphasis.
To accomplish something quickly is to do it fairly lively.
Shenanigans refers to intrigue, trickery or hidden manoeuvres designed to effect a certain outcome.
Phrases That Are Not Common in Ireland
Certain words and phrases should never be uttered in Ireland, despite the common misperception that they are 'typically Irish.' They died a death decades ago, if they were ever used at all. Such phrases include bedad and begorrah, top of the morning or faith, me darling. Calling a woman a 'fine colleen' is likely to lead to you getting a kick in the shins.
A Word of Warning
Lest you now think that you are fully armed with the right colloquial expressions while in Ireland, please be aware that the above words and phrases are only a tiny subset of the full compendium of Irish slang words. That said, however, Irish slang shares many of the same words as British slang. Phrases such as 'wuss', 'just the ticket', 'donkeys' years' etc. are in common usage in Ireland, as well as a fairly liberal dose of every Anglo-Saxon swearword9 ever uttered.
To discover more about the richness of English slang please take a look at the following entries.