that's not true...if you are willing to learn you can pronounce a new language properly despite of your age...

As we age our hearing deteriorates, so that could be a big problem or forgetting the way to pronounce words due to memory loss.

well , it depends on the health of the person ..

Some at the certain age cant pronounce well because of nerve problems.. Some even old, can speak very well because theyre still strong and healthy :)

it depends on your native language sounds too, because our capabilities to pronounce or reproduce sounds is basically related to the fact of hearing them, fortunately all languages have some flexibility and you could substitute hard sounds by similar ones and just spell the whole word in its most correct cadency..
putting the world in a generic phrase will help too much identifying it by native speakers..
just try to render the whole meaning of your phrase.

i think that if there is will all can be done:)
but anyway it is difficult sometimes for all ages

I don't think so!!
it depends on the mental ability of the person or his/her insistance of learning it's not a question of age.

We can still learn to pronounce things correctly as we get older but as we age, we lose the ability to imitate a foreign accent as well as we would be able to when we were younger.