For instance,their original Gaelic-based language is, in this country, no longer much in use - according to a gentleman who apparently knows them quite well .English,spoken with a Southern accent, is pretty much what you'll hear.
The Travellers are unrelated to the Gypsies. Gypsies are SAID to have originated in India, and speak a language which has "Indo-European" roots. In Ireland,both groups are migratory . In the USA, both groups tend to settle in close-knit communities, and travel to their working areas.
Some say the Travellers are honest tradesmen, whose reputation is spoiled by a few "bad apples". Others say MOST Travellers are bad apples.
My own guess -and it is strictly a guess-is that a society which chooses to keep itself apart, and which is not fond of "outside authority" , will not take it too much amiss if some of its members do questionable things in "the outside world". It may even celebrate the more outrageous "scores" - just as the old Irish clans, in pre-Christian,pre-Roman days , used to celebrate a successful bit of cattle rustling...as long as the activity was not conducted in their own back yards !
Apparently, they aren't Gypsies/Roma at all -- they are native Irish who became nomadic long ago.