What's the difference between yararlı and faydalı? According to the dictionary, both mean 'useful'.

Well, fayda is an Arabic word, yarar is Turkish, if you wanna know in details.
They both used in the same frequency in Turkish, I think.

Hello,

I just wanted to add that yararli is a derivative of a Turkish root, whereas faydali is a dervative of an Arabic loanword.

Fayda could be generally translated as something or some abstract concept being useful or beneficial in relation to someone or something.

In colloquial speech - Cok faydali oldu. "It was extremely useful" could also be expressed as - Cok yararli oldu, meaning the exact same thing.

Hence, the use of each word in spoken Turkish is pretty much a matter of style, and a combination of slang and jargon.

Just a few examples to illustrate this...

- Yarasin hanfendi, yarasin. Yiyin bakalim baklavalari.

The above sentence uses the verb yaramak "to be useful or usable" in a rather sarcastic tone. (Yaramak is related to both "yarar and yararli".) Perhaps the lady in reference has weight problems and is constantly on a diet etc. And maybe the cruel husband is picking on her while she has lost herself with the tasty baklava. What "yarasin hanfendi", in this case, hints at is the concept of all those baklava being consumed adding toward accumulating weight. For this sentence, you couldn't really use the Arabic loanword "faydali" without contriving the sentence.

The reason why you could not use fayda or faydali in this case is because there isn't a verb form of fayda, such as "faydamak". Almost always, when Turkish takes a loanword from another language, the tendency is to combine the loan word with a native verb form, such as etmek, olmak, yapmak etc., to verbalize the noun.

Hence, fayda (use) becomes fayda+li (useful).
Then, faydali combines with olmak (to be) and becomes faydali ol (to be useful).
This faydali ol takes the suffix -an and becomes faydali olan (something that is useful). And finally, faydali olan takes the infinitive ending -mak, and verbalizes the noun as "faydalanmak", which would translate roughly as "to make use of something or someone".

E.g.

Bu dersten cok faydalandim. / I benefitted a lot from this lesson.
Bu ders cok faydali/yararli oldu. / This lesson has been quite beneficial.
Bu imkandan yararlanmak/faydalanmak icin Turk vatandasi olmaniz lazim. / You have to be a Turkish citizen to benefit from this opportunity.

Yara+maz (useless) is also another derivative of yaramak.

Anyway, I hope this helps.

Cynicmystic you sound so familiar...