have you called?? if you have called to speak to leyla its too late she went bed an hour ago.

Perhaps I should ask this question in the language forum......but......

As aradıysan already has the conditional suffix -se why if it necessary to include eğer ???

Also - what is the difference between aradıysan and arasaydın ???

Two examples I can think of :

Beni aradıysan telefonumun şarjı bitmişti. Haberim olmadı.
Beni arasaydın telefonumun kapalı olduğunu anlardın.

Yes, you are right. But if you use "Eğer", it sound more complete to my ear. Erdinç knows better I guess since it is his profession.

'Aradıysan' is the Conditional Auxiliary of Simple Past Tense. It would translate as "if you have called me." You might or might not have called me. I don't know that.

'Arasaydın' is the Narrative Auxiliary of Conditional Tense. It is fictional (unreal). It would translate as "If you had called me."

Here is the tenses thread for further reference:
http://www.turkishclass.com/forumTitle_6_2565

Eğer can be used with the tenses below and only with them. This means 'eğer' can be used only with 'ise' (if). 'ise' and -se/-sa are the same thing. The first is the conditional conjugator and the second is its suffix version.

It is difficult to translate 'eğer'. I would translate it as "in the case of". I would say 'eğer' is the assumption or possibility of a condition.

I think in these details we see the difference of two languages.

Notice that I'm not translating 'eğer' as 'if'. We have translated 'ise' already as 'if' and 'eğer' is dependent on the existence of 'if'.

Narrative Auxiliaries (-di) of Conditional Tense: arasaydın
Conditional (-se) Auxiliaries of simple past : aradıysan
Conditional (-se) Auxiliaries of simple present : ararsan
Conditional (-se) Auxiliaries of present continuous : arıyorsan
Conditional (-se) Auxiliaries of reported past :aramışsan
Conditional (-se) Auxiliaries of future : arayacaksan
Conditional (-se) Auxiliaries of necessitive : aramalıysan