Indians/Hindi-speakers: Why do you use "f" instead of "ph" used in Urdu:

[DHONI183]

Online dictionaries suggest otherwise then why is it pronounced that way? An example possibly is the word "Phool" ('flower') from Urdu which is called "Fool" in Hindi. "Phir" becomes "Fir" and so on.

Just thought that it was an interesting thing to ask about.........

P.S.: Another interesting thing is the usage of "Z" and "J" absolutely contrary to Urdu. For example, "Darwaaza" ('door') as "Darwaaja" in Hindi, and "Jadojehadd" ('struggle'?) as "Zadozehadd".