The difference between american and british english

Hello,

Why inthe past participle the final "l" is always doubled in British English but not in American English.

For example:  

Travel – travelled (BE)

Travel – traveled (AE)

I hope to hear from you.

Will it cause confusing to if you hear someone speak American English and British English mixedly? 

I read the comments and I agree,but i like more AMerican accent, cuz I`ve heard people speaking BE and couldn`t understand what they were saying?/