Fernando 卢比奥, 2022 University of Utah
We often hear that children are amazing at acquiring their first language (L1); by the time they reach school age, they are using complex grammar and demonstrating a wide vocabulary. 更令人印象深刻的是, 这些年轻的学习者可能在学校里有两种语言，或者比大一点的孩子和他们的成人同龄人更容易地学习第二语言(L2). 儿童和成人在学习上的差异经常被用来促进一种普遍的假设, 说到语言学习, 越年轻越好. As this piece shows, the facts are more complicated. 此外, some research suggests that there are benefits to learning languages beyond developing language proficiency.
“When there are constraints on the available instructional time, 晚一点开始学习第二语言似乎是明智的，因为年龄较大的学习者可以利用他们先进的认知能力，取得更快的进步.”
费尔南多·卢比奥，犹他大学
语言习得研究的一个问题是，很多研究都集中在自然环境下(如家庭或社区)的习得上，而不是通过正式学习(如课堂)。. 也有研究表明，与年龄相关的因素使人们在一段特定的时间后不可能掌握第一语言. This assumption is called the Critical Period Hypothesis (CPH).
一些研究人员提出CPH适用于第二语言学习，就像它适用于第一语言学习一样——这意味着过了特定的年龄可能就不可能再学习第二语言了! One important focus of such research examines the influence of age as an ultimate predictor of language. 研究表明, although older children and adults may make faster progress initially in L2 learning, younger children always have an advantage in terms of ultimate attainment. This means that native-like competence and, 特别是, the lack of a non-native accent is only possible (albeit not guaranteed) with an early start (see Granena & 长,2013年).
尽管有很多研究表明，儿童在自然环境中学习语言更快更有效, 课堂语言学习与自然学习一样有助于幼儿的习得，这一点得到的支持较少. 事实上，一些研究人员(例如.g., Patkowski, 2003)认为CPH只适用于语言习得主要通过暴露发生的自然学习情境.
在包括美国在内的世界许多地方，语言课程通常被描述为“滴灌式”教学, 这意味着学生在几年的时间里每周接受少量的教学时间. This approach produces small proficiency gains (see, for example, Davin, Rempart & Hammerand, 2014), and starting earlier does not seem to make a difference (Muñoz & 位咨询专家,2019). In a large study that examined the impact of children’s ages on classroom language learning, 巴塞罗那年龄因子(BAF)项目, 这一发现得到了证实. The BAF project examined students learning English at ages 8, 11, 14岁及18岁以上, and the researchers looked at students’ progress after 200, 416和726小时的教学. The results of the BAF project showed that older starters made faster progress initially but that the younger learners caught up with the older learners in listening and speaking over time; the overall number of hours of exposure was more important than the age at which the children started (Muñoz, 2006). 其他作者也提出，第二语言学习的一个关键因素是接触目标语言的数量和质量, 2018).
In addition to developing language proficiency, language instruction has been associated with other academic benefits. 例如, 阿姆斯特朗和罗杰斯(1997), 比较一学期每周上三节西班牙语课的小学生和没有学过西班牙语的小学生, found that the Spanish students had significantly better scores on 数学 and language. 类似的, Taylor和Lafayette(2010)比较了每天接受30分钟世界语言教学的学生和没有接受30分钟世界语言教学的学生, 跨三年级,4, 和5, 在路易斯安那州. 他们检查了学生在爱荷华州基本技能测试和路易斯安那州21世纪教育星际网赌登录计划中的测试成绩. 作者证明了, for each additional year of world language instruction and controlling for other factors, 学习世界语言的学生在各个阶段的表现都明显优于非世界语言的学生.
Why do young children and adults acquire languages in such different ways? It may be that different learning mechanisms are more appropriate for different age groups. 例如, DeKeyser(2003)认为，儿童是隐性学习或在自然环境中学习，但他们需要大量的输入才能做到这一点. 另一方面, older learners have cognitive skills from having learned in formal settings, and they can learn in classroom settings. Long(2013)提出，指导二语学习的最佳情况是让学习者尽早开始学习提供“准自然主义”接触的课程，这是典型的语言沉浸式设置. 在这种情况下, young learners could still take advantage of their implicit learning mechanisms and, because of their length of exposure to the language, they would be able to reach high levels of proficiency.
Recently, dual language immersion (DLI) programs have become popular in the U.S. 在犹他州, 该州遵循50/50的DLI模式，这意味着学生从一年级开始到整个小学都有同等数量的英语和其他语言的接触. 这种教学模式, which means the language is taught through school subjects like 数学 and social studies, is closer to the naturalistic setting described above. 多年来在犹他州DLI项目中收集的数据表明，孩子们达到了很高的熟练程度(瓦钦格-萨普), 卢比奥 & Tharp, 2018; Watzinger-Tharp, Tharp & 卢比奥,2021). 如此早的开始和如此注重输入意味着他们的熟练程度在早期之后继续以稳定的速度发展. In this learning context, an early start results in very positive outcomes.
Learning language has positive impacts both in the language classroom and beyond. 关于年龄对第二语言习得影响的研究结果对课堂学习至关重要，因为它们可以告诉家长和管理者引入语言学习的最佳时间或语言课程的最适当持续时间. 来自研究的证据表明，当孩子们在接近自然环境的情况下接触语言时，早期开始可能是有利的:内隐学习和长时间的大量输入. 另一方面, when there are constraints on the available instructional time, 晚一点开始学习第二语言似乎是明智的，因为年龄较大的学习者可以利用他们先进的认知能力，取得更快的进步.
