Is age the most important key factor in pronunciation achievement?

Some people study the factors which influence pronunciation achievement the processes which are: personality, sociocultural factors, age, aptitude, exposure and role of the first language; of course, all of these factors are important. However, as being a teacher for kids for such long time, I could notice that the age is the most important factors for a person to have good pronunciation, but why? There are many reasons why I believe this.

First of all, when kids are exposed to the language they tend to learn faster than adult and they are not afraid to make mistakes. According to Karen Lund (2003), who is senior lecturer, PhD (Danish as a second language), she believes that around the age 5-6 there can be pronunciation features in the new language that one never acquires, this applies both to suprasegmental features as intonations, stress and rhythm and to segmental features such as quality vowels and consonants.  

Second, kids’ brain is open for new in-put vocabularies, expressions or structures. Once they are exposed to the language early they tend to be more fluent and have better pronunciation than the ones who were not. Moreover, a study was made by a neuroscience for kids consultant, Melissa Lee (2002), says that if a person is not exposed to a language during the childhood, he or she will never be able to speak the language as well as someone who learned language normally. Although, it is said to be able to learn many vocabulary words, but will probably never reach a normal level of speech.

Third, on the other hand there are some people who believe that age is not important to acquire a good pronunciation because there are other factors more important than only being exposure to the language early. However, I still agree that the sooner to learn the language the better for the oral and speaking skills.

Finally, the factor which influence pronunciation achievement the processes is just a matter of what people believe the most. As I said before I do believe that the age is the most important due to researches I have read and by teaching young learners for so long I could notice their ability to achieve their language proficiency and have good pronunciation.