You wrote:

Why do many consider that they have to be arabic?

ignorance.

Quote:

As an example, why is it acceptable to name someone Isa and not acceptable to name that same person Jesus?

arabic names sound nicer.

that's with all languages.

The Arabic name is preferred over the Christian version because it is more identifiable as a "muslim name" on hearing. there is nothing wrong with using the Christian, hebrew versions i suppose. Preislamic names are even acceptable, since sahabah used them and were allowed to retain their names after entering Islam so long as they did not have bad meanings. I can think of one preislamic name i love.

you know i'm bengali and they have traditional bengali names out there, but some are associated with the hindu faith, or have bad meanings so those a muslim bengali should steer away from. But anything that does not have a bad meaning is fair game. Bengalis like to choose insane names, they like to make their kids names rhyme, so if one daughter is called julie, the next will be called, shooli, rooli, i am serious looool. If there is no name they will make a name up literally, it will be a unique name. I recently found out Indians i.e non muslim Gujeratis, punjabis do a similar sort of thing that explains where the bengalis got the tradition.

Failing the ryhme game Bengalis will use alliteration. So i have a Arabic name, my sisters is persian i think, but my folks made sure both names had a similar ring both our names start with the letter "s". Brothers likewise.

But as muslims aren't we supposed to try and pick the best of names, since it is believed names can reflect a part of our traits, character? i.e Abur-rahman, Fathima Az Zahra etc etc.