I have had that problem too. It is a long process...having to swap your whole vocabulary for things that are "acceptable" for a man to say. You don't -HAVE- to change anything about you if you don't want, but if you want to talk like a man, I have some tips.
First, don't talk nearly as much. That was my problem--I'm a chatter box. Men are very direct and will say "This did this." Women are more inclined to say, "I think this did this." Men are sure even if they're not (if you understand what I mean.) At home with my boyfriend, I'm very talkative, but in public I switch to "man mode." I also do a lot less smiling, and my smiling is a lot more soft. It helps me pass, but everyone has their own way.
I say "man" a lot more than normal (but unless you wanna look like a tool, don't say "bro"). Guys will say "Hey, man." Girls will say, "Hi!" It's little things like that. Just people-watch around and see how boys talk, how they stand, what inflection they make. Talking like a boy isn't just lowering your voice!
Good luck Jossef.
