Of course it is possible, but it is quite difficult. It is easier for children, and generally gets harder with age.
But it also holds true that it gets easier to learn new languages, if you do it a lot. I've heard a lot of people say that it gets easier after the fifth language. I'm only up to four (Norwegian, English, Japanese and French - with a basic understanding of other European "dialects" - German, Spanish, Italian -- and of course "Scandinavian dialects" of Swedish and Danish) -- and I can imagine that if I learned one more "truly distinctive" language, like Finnish, or Mandarin -- I'd start to know more of the "possible ways" we use sounds -- and it would therefore be easier to choose "the right subset" for a new language.
In addition to mimicking accents, singing can be a very useful way to train pronunciation.
But it also holds true that it gets easier to learn new languages, if you do it a lot. I've heard a lot of people say that it gets easier after the fifth language. I'm only up to four (Norwegian, English, Japanese and French - with a basic understanding of other European "dialects" - German, Spanish, Italian -- and of course "Scandinavian dialects" of Swedish and Danish) -- and I can imagine that if I learned one more "truly distinctive" language, like Finnish, or Mandarin -- I'd start to know more of the "possible ways" we use sounds -- and it would therefore be easier to choose "the right subset" for a new language.
In addition to mimicking accents, singing can be a very useful way to train pronunciation.