Step-by-step explanation:
Hello,
British english is called king's and queen's english because it is associated with royal family language in UK.And,seems to be more polite than other two former languages.Stressed vowels are longer in American english but not usually in British english.These three languages have variance in speaking tone,spellings,grammars,etc.And,british and american english is more in practice.It is also said that it is not good to mix these varieties in one writing or use.
Have a nice day for you also and keep smiling :)
Welcome