well in my point of view i don't think so , because when you learn a language you're learning a new way to speak or to express your slef . so you still have the same charcter the same thoughts . but all you do is to say them in a new language . 
But when you go al live in the country your trying to learn its language , well maybe in that cause you'll change and your way of thinking and acting well changes
in the end it all depends on your real chartcter :) 

My first essay

I am Russian. I want to speak English very well. I <em>am now reading an </em>english book <em>called</em> "The forsyte saga". I've read <em>the </em>1st volume of it. There <em>are</em> sentences <em>in</em> this book which <em>are</em> hard to translate even though <em>I</em> use "Complete English-Russian dictionary". But the hardest piece of text for me have been old Jolyon's will in the end of 1st volume. There was judicial language. It is very difficult to conceive speech of English. Once upon a time I've tried to watch my favourite serial "Columbo" without translate to Russian and without subtitles. I have apprehended almost nothing. Twenty per cent is at best. For example, I have understood phrase "take it easy" at once since I know it, and the like. It would be soundly to mix to somebody on English. I have lately searched site which gives this possibility. Many people recommend Facebook. However, it is incomprehensible in what way should be behave there to reach own purpose. It seems to me that I have written enough today. Thank you for your attention.