Why do i have a screwed up voice?

basically, my family are all scottish, perfectly scottish accent, but then there's me. I went to speech therapy at about the age of 5 - 8, they didn't help at all, and it sucks cause a lot of the time i have to repeat myself, unless i'm with friends , then i don't.. if i try to speak clearly, i can, but it's annoying having to try all the time..truth be told it damages my self confidence quite a bit.. also when it comes to pronouncing R's... i fail... I'm 14 and my voice is getting deeper, think this might go away as my voice breaks? And any ideas why i talk like a weirdo? people say it sounds irish/swedish/welsh/austrailan... i just dont know anymore to be honest :P