Yes - word for word translation - I am sorry girl.
However in the english language on both sides of the Atlantic - and to the best of my knowledge - wherever it is the daily spoken language - I think you will find that the term "girl" and also "boy" - when used directly to the person being spoken to - especially if not familiar with that person - would be derogatory; ie - as if speaking to a servant.
If you accidently bump into a girl on the street you aro not going to say " I am sorry girl". In the UK, as mentioned earlier, we have many many terms of endearment that we use daily with strangers - and 99.9% of the time one of these would be used, including "hen" in Soctland - "pet" In the northeast of England - "love" and "duck" in the mdilands - and in London and the south it is not uncommon to hear "Sorry darling".
As you say Helper - it is all in the translation - and to do this successfully you have to be reasonalby knowledgable in both languages.
I would certainly NOT recommend to someone from Spain or the Latin countries to use ther term "girl" or "boy" in this context.
As I said earlier, my Castilliano is a little rusty but I do converse most days of the week in Portuguese with family and friends on the web.
At the end of the day, it isn't the translation of the words that count - it is the translation of the idea.
Incedently - when I am shopping in Brazil I regularly call the shop assistants "amor", which although not 100% politically correct - certainly gets me good service and a smile.
