One possible version:

Dear Mr. Breeze:

     I've returned home sound and safe. Thank you very much for your help and kindness while living with

your family.

     As you know, when I first set my foot in Britain, I felt quite shy and nervous, for I was not good at

 English. However, it was you who often encouraged me to interact with others. As a result, my

communicative skills gained in fluency and accuracy. What's more, you are very kind to spare nearly an

hour every day to help me practice my spoken English, which greatly built my confidence. During my stay

in Britain, you always did what you could to help me out of culture shocks I suffered. Therefore, no words can better express my gratitude to you. Without your help, I couldn't have made such great progress in

English.

     Best wishes to you and your family!