Spoken is the most difficult to be fluent. Would you like to help me to improve it?

Since my job needs to talk to client on the phone in English, I want to practice the skills for me to handle easily. Sometime I understand what they say and what they want, but I can't express my meaning and i will be very nervous. Can you help me to comfort to speak English. Or if everyone has same problem, hope we can chat together too.  

hi…i have the same problem….i understand but when i try to speak i do not what to say….i get nervous…. i would like to improve my english with you…my msn is beatriz _ monge at hotmail. dot com