If you are a heritage student of Chinese or if you are learning another language related to your birth place or family, don't give it up just yet!
A study in 2015 did research on the linguistic memories of Chinese children who were adopted by French-speaking families at 12 months. The results indicate that these children's brain response to tonal sounds is similar to that of bilingual children in French and Chinese, suggesting the brain of Chinese adoptees recognizes the tonal feature of the Chinese language. The full article, ‘Lost’ first languages leave permanent mark on the brain, new study reveals, is available on the Guardian.
Another recent study supports this hypothesis, suggesting that if you were exposed to a language as young as a prelinguistic baby, your brain actually remembers and retains this ability in your adulthood. Simply put, one can in fact "re-learn" one's first language. Read the full article, Babies Remember Their Birth Language, on BBC News.
According to the definition by New York University, Heritage Students are:
1) learners who were born in a Chinese speaking country but grew up in a non-Chinese speaking environment
2) learners who were raised in a home where Chinese was spoken
3) learners who have lived in a Chinese-speaking country for a extended period of time