Role of tone in accent+possibillity of reducing hardaccent?

ok i ve been noticing something strange from the speech of normal and common people in nearly all native english speakin regions.
That there is a particular tone in which a person with a particular accent speaks and its quite obvious in americans.
people like us whose mother tongue is not english feels it much for e.g. me i am learning american accent i almost give proper time and phsyical component movement to each american sound, seecondly itry to follow all intonation stress rules but theway or the tone in which i speak seems to be like my native accented tone.
When i mimic tone of an american from movies or from normal common life and perform all the pre-requiste of american accent alongwith people cannot judge any non american traces in my speech.
Its not that intonation or speech music that sounds peculliar to me in american people but its something like tone try to notice it by listening any non native english speaker and then imitate his tone and speak you will notice the difference.
I need all your comments.
Secndly is there something like theysay in karate classes that you can only learn karate or stretch your body to extreme when you are quite young because in later stages your bones are accustomed to the tight posture of your body or theyare hard and you cannot bend yourself like gymnasts, even if you practice alot.
So is it thesame case with people with hard accents that they cannot losse their vibrations completely or easy because their vocal chords get rigid with passage of time.

<< Secndly is there something like theysay in karate classes that you can only learn karate or stretch your body to extreme when you are quite young because in later stages your bones are accustomed to the tight posture of your body or theyare hard and you cannot bend yourself like gymnasts, even if you practice alot. >>

As anthing becomes bigger/increases in size, the bending stesses that work against this increase rise by a fourth power where as the resistance
only rises by a cubic power.

hmm,
i really don't agree to " secondly, is there something like they say in karate...................."

it depends upon Ur will power and Ur determination. No time or age gonna effect U anyway.

just think U can do anything in the world and keep on thinking it with persistent work towards it, no wonder U'll get what U desire.

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regards

Young bones do not bend more easily so much as they can be damaged without producing immediate symptoms. The symptoms appear years later. Older bones produce symptoms right away. Many athletes who overextend themselves in youth without realizing it discover years later that they actually seriously injured themselves.

There is no "fossilization" of accent in human beings. Nothing changes in the physiology of your vocal tract that prevents you from learning any language at any time. It's all in the brain, and it's under voluntary control. What his means is that you can (in theory) learn to speak any language without an accent at any age, given time, practice, and motivation. Those who claim that there are physiological barriers to this are usually making excuses for their own inability or unwillingness to eliminate an accent. (The ones who make such claims always seem to be the ones with strong accents.)

I'm not aware of any noticeable tone distinctions in English; tone is not phonemic in English and can be ignored. The intonation of British English is somewhat more variable than that of American English, but it is neither a big nor an important difference.

Young bodies have more flexibility and are able to recover faster than old ones. Some old people who are athletic try to compensate for this by self-injecting artificial GH and testosterone. Whether symptoms that pop up later in life are caused by specific activities done in youth is entirely moot. But older people are generally weaker, have lesser bone density and tend to have higher incidence of osteoporosis. Interesting subject but I don't fully see its relation to accents. But that's bones out of the way.

As it's more difficult in terms of effort required and takes longer for an older person compared to a young one to adapt to some physical ability, such as lifting a certain weight, the same can be applied to linguistic ability. In practical terms, it takes many more hours to teach an elderly debutant the ABCs of an undiscovered language or to hit basic groundstrokes in tennis for his first time, compared to a 5 year old kid who has never seen a tennis racquet.

The common thread between the two, that is between linguistic and physical abilities, isn't so much the physical body - bones, muscles or other tissue, but the Central Nervous System and the Brain. So the younger you start learning a skill, the better off you are.