Unofficially, thousands. Obviously, English, Welsh and Gaelic. Because immigration is open throughout the EU, there are many people who speak Polish, French, German, Italian, etc. There are also large populations of speakers of Hebrew as well as South-East Asian languages. There is also Chinatown, in London, with lots of Chinese speakers. There are some people who can speak local languages such as Cornish. There are many dialects of English spoken as well. For example, some words such as porkies (lies), butchers (look) and scarper (run/go) are commonly used in some areas, even though they originate from Cockney rhyming slang, which has long since died out.