guess this has a lot to do with your current English knowledge,including pronunciation,vocabulary,grammar,and understanding of English.I do not agree with learning a language in a short time.How short?One week?one month?It is hard to say.
If you are really interested in English,you will surely make progress if you keep working on it; if you are not interested and don't persist with it at all,it will become really difficult.To speak fluent English is not too difficult provided you practice enough with enthusiasm; but to speak perfect English,or,in other word,as well as you speak Chinese,will be very,very challenging.
Frankly,I think I speak English well,meaning I can express myself clearly and accurately in English.But I am not at all satsified,as each time I speak I feel that it is not a language of my own,that it is different from I speak Chinese!
Therefore,I am a little frustrated.But I won't give up trying.I wish that I could really feel that I am using this language as I use Chinese some day.How much longer time I need before I achieve this goal is yet to be found out.
Last,let me reassure you that it is not difficult to speak English well if you keep practicing!Easier said than done,not many people can KEEP going,and there are another major group of people who are always struggling with opening up their mouth to utter their first English sentence.Once they succeed,they will get over the first stumbling block,and it is not too long before they can surprise themselves!