It may quite obvious to everybody else but to me my conclusion was a bit new discovery. I concluded that words bear different meanings as they travel from one country to another over time. Darling may be a common word now in India among middle class and understood widely having same connotation as in England but a decade ago it was like a special word which was only used to call your intimate partners. To some extent, credit to such things goes to cinema from where people pick them up without knowing their real meaning and context. They start using it in the same way they have seen it being used in the cinema.