两国历史渊源很深，所以是互相影响的关系，以前是法语影响英语，进入现代这种影响开始反过来了。所以英语里很多高端词汇都是法语来的，而法语中很多新兴词汇也不再予以翻译直接使用了。
看看这篇外网介绍法语对英语影响的文章吧，中英对照~
Bill Bryson calls the Norman conquest of 1066 the "final cataclysm which awaited the English language." When William the Conqueror became king of England, French took over as the language of the court, administration, and culture - and stayed there for 300 years. Meanwhile, English was "demoted" to everyday, unprestigious uses. These two languages existed side by side in England with no noticeable difficulties; in fact, since English was essentially ignored by grammarians during this time, it took advantage of its lowly status to become a grammatically simpler language and, after only 70 or 80 years existing side-by-side with French, Old English segued into Middle English.
比尔·布赖森把1066年诺曼人对英国的征服叫做“英语最后的大变革”。自征服者威廉成为英格兰国王后，法语就成为了法庭、行政和文化教育领域使用的语言，而法语的统治也长达300年。而这期间英语就变成了日常生活中平民使用的语言。两种语言自然而然的就同时存在于英格兰。这一时期文法学家们都无视英文，而其卑贱的地位反倒使得英文成为了一个文法相对简单的语言，约7、80年之后古英语就完成了像中世纪英语的转化。
Vocabulary
During the Norman occupation, about 10,000 French words were adopted into English, some three-fourths of which are still in use today. This French vocabulary is found in every domain, from government and law to art and literature. More than a third of all English words are derived directly or indirectly from French, and it's estimated that English speakers who have never studied French already know 15,000 French words.
词汇
在诺曼人统治期间，约有10000个法语单词被英文采用，其中约四分之三至今仍在使用。从政府、法律到艺术和文学，各个领域都有这些法语词汇的身影。而三分之一的英语单词都是直接或间接从法语演变而来的。评估显示，即便没有学过法语，一个母语为英语的人都能辨认15000个法语单词。
Pronunciation
English pronunciation owes a lot to French as well. Whereas Old English had the unvoiced fricative sounds [f], [s], [θ] (as in thin), and [∫] (shin), French influence helped to distinguish their voiced counterparts [v], [z], [ð] (the), and [ʒ] (mirage), and also contributed the diphthong [ɔy] (boy).
发音
英语发音的形成很大程度上也要感谢法语。古英语中有清音摩擦音[f]，[s]，[θ]，法语的发音就有助于将它们与对立的浊辅音[v]，[z]，[ð]进行区别。此外[ʒ]和复合元音[oy]的也是由法语演化而来的。
Grammar
Another rare but interesting remnant of French influence is in the word order of expressions like secretary general and surgeon general, where English has retained the noun + adjective word order typical in French, rather than the usual adjective + noun used in English.
语法
还有个在英语中比较少见但是很有趣的法语影响就是词组中的单词顺序，比如秘书长(secretary general)和卫生局局长(surgeon general)这样的词。英语中的这些词保留了法语中的一般名词+形容词的语序，而非使用英文中形容词+名词的顺序。
(资讯来自about.com，整理和翻译为“沪江法语”原创，转载请务必注明)
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