Besides, Arash has not really mastered the language; he has not attained the same level of native American speakers. So we can conclude after this brief analysis that Arash has not acquired English an instinctual way.
On the opposite, Mircea is an eight years old, Romanian boy who has who has never been exposed to English. He enters an American public school at the age of eight, hence during the critical period. After only one year he speaks almost as native speakers with the American accent, he masters grammar and vocabulary and all this without struggles or effort as it seems. As we know, an instinct happens to everybody and does not need prodding to happen. Consequently we can consider that Mircea has acquired a second language in an instinctual way. Yet, what are the factors that have lead to these differences in the learning process of the second language in the case of these immigrants? .
Actually many factors affect the rate and the way we acquire a second language. One of the most important one is the relation between age and learning. If one has ever been familiar with immigrant's experience in America, he would have been sure that Mircea is not an overtalented child. In most immigrant families the child soon becomes the interpreter for his parents that have not learned the language. These children indeed speak approximately like native speakers whereas this is impossible for adult learners. Many researchers have justified this phenomenon through the critical period hypothesis. Children are superior to adults in learning language because their brains are more flexible and their cortex is more plastic. One interesting analogy compares our brain to a computer. Similarly to the computer that we get with preinstalled software, our brains have a special area for learning language, which is pre-wired for assimilating vocabulary, grammar, and syntax. In addition during the first year of life this wiring is extremely flexible and efficient but unfortunately this flexibility in the brain disappears with age; hence our brains become rigid and it becomes very hard to acquire a new language.
