It's English. Fra Et Hib Rex is Latin, meaning Ireland, France. Caro DG Mag Bri meaning Charles by the grace of God King of Great Britain. I think this is a copper farthing.
Yes it is a Charles I farthing from Britain. I think it is "Richmond" type, but within that there are numerous minor variations. Dates between 1625 and 1649. Minted for use in the whole British Isles, which included all of Ireland at that time. Not as scarce as you would expect, and getting more common as the metal-detectorists over here get better equipment. It is in quite good condition - I would expect it to make GBP 5 to 10.
Neither of those are the mint mark - they are part of the standard design. The mintmark appears just before the word Caro on the crown side, but is badly obliterated. If you can get a better idea of what it is, it may help clarify which variety and narrow down the date.
Helmet or Halberd are quite likely. I am pretty sure this is a Richmond Type 2 Farthing because of the Colon stops. Price and scarcity as before.
Thanks a lot everyone for the answers! Now I now its value thanks! I think its a great coin for that amount of money.