I asked because somebody who told me in the past sağol nowadays are saying teşekkürler

eskiden bana sağol dediğin birisi şimdi teşekkürler diyor diye sordum

Eskiden bana sağol (dediğin) diyen birisi şimdi teşekkürler diyor

My try...

 demek = to say,to tell

 diyor = he/she/it saying

 diyen = the person who says [said] [ the person who tells [told] ]

de [the stem of the verb ["e" changes into "i" ] + y [buffering letter to conjugate two vowels ] + en [ that, who ]

Sağ olmak ( sağoll)

yes..indeed..I have realized my mystake after I posted it...it is strange to think in romanian and than in turkish but trying to translate from english to turkish, because all of my books are turkish to turkis or english to turkish..tekrar çok teşekkür ediyorum tunci

but what is the difference between diyen and denen...please take a look here

Sevgi denen o gerçeğe - as I think you know it is a lyrics of Kıraç - Mutlu olmak istiyorsan;

if I am thinking a bit, translating it in my mother language - romanian, is is simple..but if you ask my to tranlate `somebody who said` my point of view is to say denen birisi

Denen comes from denemek or denenmek: to try/to test and to be tried/to be tested

Diyen comes from demek: to say.

My try...

If I was asked I´d say

         demek ´to say´ > diyen

         denmek ´to be said´ > denen

That´s why

         Sevgi denen o gerçeğe ´something that is called love´ (passive voice)

         sağol diyen birisi ´someone who says...´ (active voice).

This word is come from (say) İt s mean say from someone -Denen -Söylenen-Denilen (They are all same mean)

oh..yes..yes..indeed..thank you Abla