English really is important for me?

2007 is past and 2008 is coming, it is time for me to try for getting a raise, but I know clearly that I can hardly get a satisfying salary increasing since my poor english, as an engineer in automotive electrnics industry, the most mainly duty of my work is to provide the customers the supports on technical and application for the products we distribute, as the headquarters in America, we have to comply with the direction from Amearica, accepte the training, place the order, process the shipping, and etc, nevertheless, for me, all goals is to support the customers in China, so I concern that english is not critical, but my boss who is the english-speaker and can speak chinese well do not think so, therefore, my raise requests were refused again and again, the result of annual reviews is not good as my wishes, of course, my salary is lower than the people with the same qualification, as a Chinese, for living, I have to study hard English, a foreign language and put it the first, I wonder why I must study the english and how can I enjoy while study? I am always confused with the current facts in China, 5 years ago, I had to resigned my work from previous company owned by country in Northeast China due to unefficient and low pay, then moved to Shanghai, the most developed city in China, work for current America company since there is no chance for me to find a job from local companys, I have to work for foreign company and try to speak other language however I am so unwilling.