语言是交流的工具，民族的成长离不开语言。
历代王朝，若边境无战事或其他侵扰，就会在边关设市，与周边民族开展贸易，互通有无，交往的层次逐步提升，从事翻译工作的人员便应时而生。
《礼记·王制》曰：“五方之民，言语不通，嗜欲不同。达其志，通其欲，东方曰寄，南方曰象，西方曰狄鞮，北方曰译。”意思是说，这些从事翻译工作的人员，在东方称作“寄”，在南方称作“象”，在西方称为“狄鞮”（本意为用动物皮革做称的鞋子）、在北方称作“译”。
外语学习及翻译推动民族发展对外交流，也使本民族在认识他者的习俗、文化、科学的过程中不断成长。十七世纪英国思想家约翰·洛克（1623--1704），特别强调算术和几何在教学中的重要性，认为这些学科能培养学生的抽象推理能力。另外，约翰·洛克还强调外语学习的重要价值，认为英国的孩子“一到能够说英语的时候，他就应当学习别种文字。”[1]
学习外语也有助于开发智力。人脑是分区的，左脑区和右脑区承担着不同的功能。左脑是认知与思维的发源地，主管逻辑、语言、数学、文字、推理及分析；右脑是创造能力和感悟的发源地，主管图画、音乐、韵律、情感、想象及创造。Pascal Picq等四位法国籍学者，在其著作《美妙的语言史：从猴子的啼叫到莎士比亚的戏剧》（La plus belle histoire du langage: du cri des singes aux dialogues Shakespeariens）中，在脑区功能问题上提出新的见解，认为双语有助于开发不同脑区的功能：“两门语言分别激活不同的区域，其中母语激活左脑，第二语言激活右脑！”
以下这几段英文（选自网上，经过笔者编辑），也说明语言经由两个脑区的处理，说明上述法国学者的观点不无道理。
The Functions of the Two Sides of the Brain
The right hemisphere of the brain deals, to a greater extent, with the following functions: the consciousness of oneself; recognizing our image in a mirror; facial recognition; processing the emotional part of language, such as prosody and intonation; feelings associated with intense romantic love; managing visual-spatial attention.
The left hemisphere of the brain is responsible for: understanding and producing language; mathematical abilities and recalling facts; processing attractive faces.
The Two Hemispheres and Brain Lateralization
Brain lateralization is the idea that some brain functions rely more heavily on one hemisphere than on another. One example of this is when we process language. The left hemisphere is in charge of language processing for the most part, whereas the right hemisphere only processes verbal information in relation to emotion. However, it has recently been discovered that speech is processed in both hemispheres equally, so perhaps language is not as lateralized as we previously thought.
Likewise, it was believed that a left-handed person’s brain was less lateralized for language development. That is, it was believed that these people would use more of the right brain hemisphere for language, contrary to the general right-handed population. It has been proven that this only happens in 1% of the left-handed population.
It was even found that the degree of lateralization of some brain functions may vary from individual to individual.
Our brain is lateralized in some of its functions, however, most of these happen in both hemispheres. If a brain region or even a whole hemisphere is damaged or destroyed, other neighboring areas or even the opposite hemisphere may, in some cases, take over the activity typically performed by the damaged region. When brain damage interferes in the connections between one area and another, alternative connections can be developed to bridge the difficulties. This is only possible thanks to the brain’s great ability to adapt, which is called brain plasticity.
（方开瑞）
[1] 转引自（日）佐藤正夫：《教学原理》，钟启泉译，北京：高等教育出版社，2006年，第104页。