1.They are called world Englishes and they include Canadian, Britain, American, Australian and Indian English.
  它们被称为世界英语,即包括加拿大英语、英国英语、美国英语、澳大利亚英语以及印度英语。

(1)they are called...是一个被动语态结构,意思为“被称为;被叫作”。例如:
  Do you want to be called Miss or Mrs? 你想被称为小姐还是夫人?
(2)Englishes 在此作为复数形式,意指不同国家的英语。例如:
  There're actually several Englishes in the world, such as American English, British English, and so on.
  实际上世界上的英语有好几种,例如美国英语、英国英语等。
(3)include v. 包括;包含(某人或某事物 )例如:
  The cost of the car includes taxes. 汽车的费用含有税收。
  Fifteen persons were present, including the chairman.
  有十五人到场,包括主席。

2.... where English plays an important role as a first or second language,...
   ……在这些地方,英语作为第一或第二语言起着重要的作用,……

(1)where 引导的是一个定语从句。如果被修饰的先行词是地点,则引导词选用where。例如:
  This is the village where Chairman Jiang has visited.
  这是江主席曾经访问过的村子。
(2)play a role意为“起……作用;扮演……角色”。在实际运用中,常在role 前面加一个修饰性的形容词,如important, significant, useful等来加强语气。例如:
  Science plays an important role in developing agriculture.
  科学在农业发展中起着重要的作用。
  China is playing a more and more constructive role in the world affairs.
  中国在国际事务中正扮演着越来越具建设性的角色。

3....either because of foreign role or because of its special role as an international language.
   ……或者是因为外来统治,或者是因为作为一种国际语言的特殊作用。

(1)either... or...意为“要么……,要么……;或者……,或者……”。本连词结构可以用来连接两个或更多的单词、短语或句子。例如:
  She is the kind of girl you either love or hate.
  她是那种要么让你爱,要么让你恨的女孩。
  It's either pink, red, or orange.
  这颜色或者是粉红,或者是红,或者是橘黄的。
  Either you come here or I go to pick you up will be OK.
  你自己来也行,我去接你也行。
 注:either... or... 结构在句子里作主语时,句子的谓语要和or 后面的部分在人称和数上保持一致。例如:
  Either the dog or the cat has eaten it.要么是狗,要么是猫把它给吃掉了。
(2)because of意为“因为;由于”。例如:
  She walked slowly because of her bad leg.
  她走得慢是因为腿有毛病。
  Because of the bad weather, they didn't go outing.
  由于天气不好,他们没有出游。
 注:要注意because of 和because 的区别:because of是一个介词词组,后面跟名词性的词或词组,不能跟句子;而because是一个连词,后面可跟一个表示原因的状语从句。例如:
  She was very excited because she got the first prize in the singing contest.
  她非常兴奋,因为她在唱歌比赛中得了一等奖。

4.So when you hear two native speakers of English, ...
  因此当你听到两个生来就讲英语的人谈话时,……

  native adj. 本国的;本土的 例如:
  He is a native English. 他是一个正宗的英国人。
  What's your native language? 你的本族语(母语)是什么?
常用搭配:native speaker (说母语的人) native New Yorker/Londoner/Californian...(老纽约/老伦敦人/老加利福尼亚人……)例如:
  He's a native speaker of English.
  他的母语是英语。
  I began to live here from birth. You can call me a native Londoner.
  我生来就住这里,你可以称我为老伦敦。

5.Would you come up to my flat for a visit?请到我们公寓里来坐坐好吗?
(1) come up 来;上来;升起;长出;出现 例如:
  An old friend of mine came up to my house yesterday.
  我的一位老朋友昨天来我家了。
  The grass is beginning to come up.
  草开始长出来了。
  The sun is coming up from the east.
  太阳正从东方升起。
  I'm afraid something urgent has come up. I won't be able to see you tonight.
  很抱歉有些急事,今晚不能见你了。
(2) flat在英国英语里指公寓式楼房一套房子,而美国人则称之为apartment。

6.The English spoken between about AD 450 and 1150 was very different from the English spoken today.
   公元450到1150年之间,人们说的英语跟今天所说的英语就很不一样。

  AD是拉丁语anno domini 的缩写,意思是“公元”;而BC 则是before Christ 的缩写,指的是“公元前”。例如:
  He was born in the year 55 AD/BC. 他于公元/公元前55年出生。

7.So why English changed over time? 那么英语在一段时间里为什么会起变化呢?
  over prep. through a period; during 贯穿(一段时间);在……期间 例如:
  I often work over night when the exams are near.
  当考试临近时我常常通宵学习。
  Can you stay over Sunday?你能过了星期天再走吗?
 注:如把over 和time写成一个单词overtime,意思就成了“加班时间”。
 例如:
  I've six hours' overtime this week, so I'll get my overtime pay.
  本周我加班六小时,因此我会得到一些加班费的。

8.Actually, it was based more on German than present day English.
  事实上,当时的英语比现代英语更多地依赖德语。

(1)该句的主句是被动语态句,也可以写成主动语态:
  People based English in those days more on German than...
(2)based on sth 以某事物为另一事物的根据、证据等。例如:
  He based his theory on other people's researches.
  他把自己的理论建立在别人的研究基础上。
  My conclusion is based on facts, not on imagination.
  我的结论以事实为依据,不是凭空想出来的。

9.It became less like German, and more like French because those who ruled England at that time.
  它不那么像德语而更像法语,因为那时的英国统治者说法语。

(1) less like...(不太像……) 和more like... (更像……)这也是一种比较级结构,和系动词连用。例如:
  She looks less like her mother, and more like her father.
  她看起来不太像她的母亲,而更像她的父亲。
  The car of this type seems more like a plane.
  这款车似乎更像飞机。
(2) who ruled England 在此是定语从句,修饰先行词those。再例如:
  Those who haven't done their homework will be punished by the teacher.
   那些没有做作业的学生会受到老师的惩罚。

10.In the 1600's, Shakespeare made use of a wider vocabulary than ever before.
   17世纪,莎士比亚所用的词汇量比以前任何时期都大。

  vocabulary n.(一种语言的)词汇;字汇 例如:
  We must enlarge our English vocabulary in the middle school.
  我们在中学时必须扩大英语词汇量。
 注:word n. 词汇的独立单位;单词 例如:
  He can memorize 30 English new words a day, but his vocabulary is still small.
  他一天能记住三十个英语单词,但是他的词汇量仍然不大。
  从上例可见,word指的是单个独立的单词,前面可以用数词来修饰;而vocabulary则指一门语言的词汇,不能用数词修饰。

11.One big change in English usage happened when Noah Webster wrote the American dictionary of the English language, giving American English its own identity.
   英语用法发生了一次大变化,那就是在诺厄?韦伯斯特编撰的《美国英语词典》的那个时期,这本词典体现了美国英语的特色。

(1)这是一个主从复合句,主句是one big change happened,从句是一个由连词when引导的时间状语从句;Giving American English its identity 是一个现在分词短语;in English usage 作定语,修饰change。
(2)usage n. 习惯;惯例;(尤指)词语惯用法 例如:
  A dictionary of Current English Usage compiled by Zhang Daozhen is a very good dictionary that will help you a lot in English learning.
  张道真编写的《现代英语用法词典》是一本很好的词典,对英语学习大有帮助。
 注:use与usage的区别:usage 主要指语言等的惯用法;而use 指一般的用法和用途。例如:
  It's difficult to master the usage of idioms.
  掌握习语的用法很困难。
  What's the use of that broken vase? I'll throw it away.
  那个破损的花瓶有什么用?我要扔掉它。
  A little knife has many uses.
  小刀有许多用途。

12.English is also spoken in many other countries in Africa and Asia, such as South Africa, Singapore and Malaysia.
   在非洲和亚洲的许多国家,比如南非、新加坡、马来西亚等国,人们也说英语。

  such as 相当于like或for example,用以引出例证。例如:
  My doctor told me not to eat fatty foods, such as bacon, hamburgers and so on.医生告诉我不要吃油腻的食物,如:咸肉、汉堡包等。

13.Today the number of people learning English in China is increasing rapidly.
   目前在中国,学习英语的人数正在迅速增长。

(1)learning English 是分词短语作定语用,修饰people,该短语也可写成一个定语从句:who are learning English...
(2)rapidly adv. quickly 迅速地;快速地 例如:
  He had a fall, but stood on his feet rapidly.
  他摔倒了,但很快站了起来。

14.Geography also plays a part in making dialects. 地理位置对方言的形成也有影响。
  play a part:起作用;参加(某活动) 例如:
  Friends always play a helpful part in overcoming difficulties.
  在我们克服困难的过程中,朋友们总是帮助我们。
  Tom plays an active part in the local community.
  汤姆积极参加社区活动。

15.Although many Americans move a lot, they still recognize each other's dialects.
   虽然许多美国人经常搬家,但是他们仍能辨别彼此的方言。

(1) though 在句中是连词,引导的是一个让步状语从句。在这类句子中,不能像汉语的“虽然……,但是……”句型那样在主句里再使用but。例如:
 误:Although he's only ten years old, but he has learned all the college courses.
 正:Although he's only ten years old, he has learned all the college courses.
 正:He's only ten years old, but he has learned all the college courses.
  虽然他只有10岁,但是已经学完了大学课程。
(2) recognize v. 认出;识别出
  I recognized Mary on the photo although she was ten years old then.
  虽然玛莉当时只有10岁,我仍然能在照片上认出她。

16.Pardon. 请再说一遍。
  当你不明白对方的话时,可以请求别人再说一遍。比较常用的客气请求有以下几种:
  Pardon?/I beg your pardon? 请您再说一遍,好吗?
  Could you say it again?   请您再说一遍,好吗?
  Could you repeat that, please? 请您再说一遍,好吗?
  Can you speak more slowly, please? 请您说慢一点,好吗?
  Sorry I can't follow you. 对不起,我没听明白。