I’m from England, and as you mentioned, there are many variations over here just in English. A typical person with a “brummie” accent, a person from birmingham, will talk a lot faster than your average londoner. I also speak urdu/hindi and understand punjabi. Out of the three of them, urdu is the slowest, then hindi, and then punjabi. I think the manner in which a language is spoken also very much depends on the calibre of the command a person has over the language. For example. a person from South London will sound faster than a person from Oxford or Cambridge, as they will take certain “shortcuts” when talking.