As an Indian, I am sad that the world will lose out on short to-the-point words/phrases such as "please do the needful", "i have a doubt", "prepone" and many others :( We are like this only.
This one is problematic when used with non-Indians.
When an Indian says they have a doubt, they mean “I have a question and seek clarification on one point”. Someone not familiar with this Indian English idiosyncrasy will instead interpret it as “I’m not convinced that what you’re saying is true”, potentially even casting aspersions on your integrity. The question that follows will normally clear things up enough that it’s not disastrous, but it will still tend to leave a bad taste in the hearer’s mouth. It took me quite some time to really get used to it.
I imagine Spanish speakers will have no problem either.
Please explain that one to me, because every time I've heard it used it seems to amount to "I have a question," which to me is confusing.
We used to have "doubt-solving sessions" in coaching centres. Everytime one of the students would ask "Sir, I have a doubt" I would always snigger within that the student was insinuating something sinister or nefarious about the instructor's character. I always found it hilarious.
But that's just how English is used in India.