I don't think they have difrent meanings. japan just has more sub catagorys. over int he hentai discution it was mention lolicon is simply from lolita compex, wich originated from a book. by the way I beleive lolita, the girl in the book, was between 10 and 12. the term then started to be used for adult men who were intrested to little girls sexualy. now, genuinly it was not used to mean todlers. children yes, prepubesent? moestly. pretty much I would say is she is 20, or in some cases 10 years or more younger, it is a lolita complex. is it the same as pedophilia? I will say no. the difrence? with lolitas the idea is the girl, though far too young. is still enticing you. she is activly trying to get you. usualy. though it has been used for people who simply go seaking younger girls. but, the girls in the end are willing. this I will say is the fundamental difrence. now, I could be wrong. I've never really thought about this.
but now for how lolicon has been used in japanese and english. lolicon can be inocent. it can simply be you like how young girls look. you like cute things. not nesisaraly in a sexual way. like the gothic lolita trend. first seeing the githic lolita bible, and its title. I was unsure what it was trying to do, that is from a purly english point of view. but in the end, (reguardless of any fetishes and the such that people may use it for.) its simply a fasion trend. and, japan as a whole is obsessed with cute.
but then theres the lolicon that is for sexual perposes. wich is outright pedophilia no matter what people try and hide under. yes there are some grey areas, but the out and out sexualy explicit ones arn't and I would say as a whole both sides feel the same on that.
now, in japan lolicon can be fore living breithing little girls. if is any intrest in young girls drawn or not. now here we have taken lolicon, removed it from lolita complex, (because thats not good you know?) and made it more strictly for drawn little girls. and yes I know 4chan will call any little girl real or not loli, but thats 4chan and there odd, and at the same time its internet subculture wich in a sence, no one takes as real. you are talking to people you do not really know, looking at pictures if actual photos are of people far far away from you. so in a sence I would say it still not in the real catagory. and one must wonder how manny people are truely that deap or just spouting the words?
I would say they both have fundamentaly the same meaning. eccept we have made it for the dirtiest aspect while in japan it has far more levals.