I suppose you have a date picker control placed on a page that is configured to show arabic time. In Sitefinity is you create a control with RadDatePicker it will not show dates in arabic if it is not configured to load the calendar for this culture (by default is loads gregorian calendar).
When Arabic is added as a translation to the english pages the current UI culture is changed to "ar" and all controls that support System.Globalization seek to load that culture. If the RadDatePicker is configured to specifically show arabic time I think it will do so in english pages too.
Review this demo and add additonal logic to the date picker to detect the current ui culture and load different calendar when the culture is "en" or "ar".
This gets the current culture.
var currentCulture = Thread.CurrentThread.CurrentUICulture;
if this is not the case with the control can you share the control code so I can test with it at my end?
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