The Complexities of Learning Accents
One of which, is whether you are good at hearing and copying accents. For obviously this is the most important, and I have heard that being a musician helps greatly with distinguishing the accent.
Another is whether or not the language has an accent, or if it is just pronunciation.
For some languages there is one, but it is so slight, it is extremely difficult to hear. For instance, Hungarian is mostly pronunciation as every vowel, consonant and letter pair sounds the same, unlike English where it changes depending on the word. The Hungarian accent however, is very difficult to get right and is something most learners of Hungarian never manage to get quite right, even if they are fluent.
Japanese on the other hand is really just pronunciation. If you don't pronounce it right they don't understand and so the accent exists when you speak properly.
I have deduced recently that an area where most language teaching fails is in learning the accent. I believe it is necessary to learn the syllabic rhythm of a sentence; something easier said than done when nobody teaches it! The only advice I can give on this is to try and get a native speaker to show you, but then again most native speakers know only how to speak it, not the mechanics of structure and rhythm.
Every word has a number of syllables, and the sentence that word is in will have a rhythm of how they are spoken. Some words go up in tone, some go down, sometimes the syllables in a middle of a word go up and likewise some go down. Perhaps the easiest way, is to do the clapping syllable exercise, in which you clap the amount of syllables in a word (something I remember from primary school). It definitely helps when your target language begins to have longer and longer words i.e German, Hungarian, Finnish.
In the Japanese language, you pronounce the syllables, so when you say a word, you have the rhythm already and it never changes.