That's not an issue.
If you are using a multi-byte character set (UTF8, AL32UTF8, etc.) then the Arabic characters will take the same storage as two English characters.
If you don't know what character set means or don't know what it is then ask your DBA.
... then the Arabic characters will take the same storage as two English characters.
I do not believe this is correct - see http://www.unicode.org/charts/PDF/U0600.pdf
It is only Far Eastern languages that take up more than two bytes for one character.
thanks for your reply .
but i need to increase this field to add arabic month name and i can't do it now i need to increase this field to accept 10 character while writing arabic language
the table accept 15 arabic character .
so how can i do this ?
Believe me it does.
We are working based on this fact for many years and this includes both custom applications and Oracle EBS.
If you ask any implementer then he would tell you the same.