Apart from English, three Celtic languages are still spoken in the UK: Irish (in Northern Ireland), Scottish Gaelic (in Scotland) and Welsh (in Wales). In the image we can see the entrance of the Scottish Parliament, in which the name appears in English and below it translated into Scottish Gaelic. You have all the information in: «What is the language of the UK? What accents and dialects does it have?«.
You have all the information in: "What is the language of the UK? What accents and dialects does it have?".