Personally, I don't believe picking up an accent is completely dependant on age, but probably more so on how good a listener someone is.
I completely lost my Australian accent after living in Europe for a year. In that time I managed to start speaking German with more or a less a native accent, and my English changed to some sort of weird British/German mixture. It wasn't something I tried to do on purpose, it just happened and it took about 3 months for me to pick up my old accent again. In fact, I used to get sick of people asking me when I got back home if I was from England!
Someone's ability to pick up accents is also dependent upon whether he is willing to do so. I came to America when I was nine years old and have lived here for quite a long time but I don't speak with an American accent because I don't want to.
Blah, how were you able to pick up a British accent when living in Germany? Is German pronunciation and intonation very similar to British English?
I don't think so, otherwise a German English accent would be more sought after...
I'm learning Japanese now. The hardest part, for me, is the varying levels of politeness, particles, and as Hi, Bryan said, the counters. Especially the counters :@:@:@
For example:
~Mai = Counter for flat things like paper and CD's
フロッピヂスクを二十本買いました
furoppi disuku wo nijup-pon (niju hon) kaimashita
I bought 20 floppy disks
~Hai (Pai/Bai) = the counter for cups, glasses, and bowls of drinks or food
ご飯をもう一ぱい下さい
Gohan o mou ip-pai kudasai
Please give me another bowl of rice
~Hon (Pon/Bon) = the counter for long, shaped things
えんぴつが二本いります
enpitsu ga ni-hon irimasu
I need 2 pencils
~Nin = the counter for human beings
友達が三人家に来ました
Tomodachi ga san-nin
3 of my friends came to my house
~Satsu = the counter for bound books, magazines etc.
先週本を三さつ読みました
Senshuu hon o san-satsu yomimashita
Last week I read 3 books
~Hiki (Piki/Biki) = the general counter for animals, but not birds
台所でネズミを一ぴき見ました
Daidokoro de nizumi o ip-piki mimashita
I saw one mouse in the kitchen
~Tsu = the counter for miscellaneous things
四つ勉強しました
Tottsu benkyou shimashita
I studied 4 Kanji
The hard part isn't remember which counter is which, it's the way they change depending on the number. Like: Ip-pon, ni-hon, san-bon, yon-hon, go-hon, rop-pon, nana/shichi-hon. Arg!!
Counters are more a Chinese thing than a Japanese one.
English has counters for uncountable nouns, like a piece of paper.