1. Critical Period Hypothesis: One influential theory in SLA is the critical period hypothesis (CPH), which proposes that there is a critical period early in life when language acquisition is most effective and efficient. This period is generally believed to extend from birth to early adolescence, with the most rapid language development occurring during the early years of life. After the critical period, SLA becomes increasingly challenging, and native-like proficiency becomes harder to attain.
2. Accent and Pronunciation: Younger learners tend to have a better ability to acquire native-like pronunciation and accent in a second language. This is because children's brains are more adaptable to the phonological features of a language, allowing them to more easily mimic and produce sounds that may be unfamiliar in their native language.
3. Grammar and Syntax: Younger learners often show a greater aptitude for acquiring the grammar and syntax of a second language. They may be more sensitive to the regularities and patterns in language, and they may be more willing to experiment with new grammatical structures without being constrained by existing habits or beliefs about language.
4. Vocabulary Acquisition: Children generally have a faster rate of vocabulary acquisition compared to adults. They may be more curious and open to learning new words and expressions, and they may have fewer inhibitions in using them actively in speech and writing.
5. Cognitive Factors: Younger learners often have advantages in terms of cognitive flexibility, memory capacity, and neural plasticity, which can facilitate SLA. Their brains may be more receptive to new linguistic input, and they may be better at forming new associations between sounds, words, and concepts.
6. Social and Emotional Factors: Younger learners may have more opportunities for natural language exposure and interaction in social and educational contexts. They may also be less self-conscious about making mistakes, which can create a more conducive environment for language learning.
It's important to note that individual differences exist, and not all learners fit neatly into these age-related patterns. There are exceptional older learners who achieve near-native proficiency in a second language, just as there are younger learners who may face challenges in SLA. However, on average, research generally supports the notion that age is a significant factor in second language acquisition, with younger learners often demonstrating greater success in acquiring a second language.