One answer must be that names adapt to the countries' languages. Both their spelling and their pronounciation can be altered. I give you an example:
Hungary is a list-giving country where you can choose names for your kids only from a list made up by the Academy of Sciences. If you want a name that is not on the list, you can make a request for it.
The name Imogen
was added recently, in two forms: Imogén and Imodzsen.
Imogén has more or less kept the spelling, but is pronounced EE-mo-gayn (g as in go), according to the Hungarian language.
Imodzsen is pronounced like the original Imogen
, but is written down differently, because we mark the soft g sound (like in geography) with the dzs combination.
Is it clearer now?