Turkish is a wonderful language to master filled with enthusiasm and passion. After all, there are nearly a dozen different ways to call someone "darling" and nearly just as many to say the word "love." Turkish also has a number of terms that are used in specific situations and display cultural sentiments in the perfect manner. There may not be sarcasm as we know it in English, but there are definitely a number of nuances with words that make for the perfect witty response, or at the very least an appropriate display of your command of the language.
Perhaps one of the most commonly used words in Turkish is "inşallah," its comes from Arabic, but like many other similar words, it has become ingrained in Turkish and its usage is very much a reflection of the culture. "İnşallah" translates to "God willing," but it has also very much become a word used to mean "hopefully," especially when acknowledging any sort of desire or hope for the near and far future. This wonderful term can, however, be disconcerting to a foreigner especially in the case when trying to solidify plans or reach any sort of definitive outcome such as when signing a rental contract or saying you will meet someone at noon, and suddenly you are faced with the response "inşallah." However, there is no need to fret, it is in no way a sign of lack of respect toward said plans, it is simply an acknowledgement of the ever-presence of unforeseen plans for us by a greater power.
In juxtaposition, the word "vallahi" is injected in many conversations to express the validity of a statement. The closest example in English is "cross my heart" or "I swear to God" to attest to something's truth. With a varying inflection however, "vallahi" becomes somewhat of an enthusiastic question mark asking for a reaffirmation that the statement is indeed true.
My own personal favorite word is "eyvallah" and, thankfully so, it can be used in a wide variety of situations. According to the Turkish Linguistic Society, "eyvallah" means "we entrust to God" and is used in three different settings. The first being when someone offers you something you say "eyvallah" to mean "thank you." Another situation in which you can use "eyvallah" is to express your willingness to help if someone asks you for something. The final use of the word is to say goodbye, in a sort of "cheerio old chap" sort of manner. This word is more of a masculine sort of term and in slang can be used to mean "that's cool, dude," which is one I love to pull out of my repertoire when the situation permits.
"Maşallah" is also a good word to be familiar with as you may find yourself needing to use it to ward off none other than the "evil eye." Best translated as "praise be!" it is used to express appreciation, joy, praise or thankfulness for a positive event, development, item or person. However, it is especially important to use after praising or complimenting someone or a situation to ensure that the omnipresent "nazar" or "evil eye" as a result of envy does not end up altering it somehow. Say for example you compliment a baby, you must also make sure to say "maşallah" to repel the evil eye you may have caused from all that praise. The same goes for if you were to compliment a new car, a child on their grades or an engagement. Basically, the rule of thumb is if you come across something good for you or others and you want it to stay that way then make sure to work "maşallah" into your vocabulary to ensure full protection from any sort of jinx.
"Estağfurullah" is a word of politeness and grace meaning "may God grant me mercy" that is invaluable to know and you would be surprised at just how often the occasion surfaces to use it. In general, it means "not at all" or "don't mention it" and is sort of a more casual way of saying "you're welcome." However, this word also has a number of fine points befitting Turkish culture that would get you far if you get the hang of it. Apropos to the Turks, "estağfurullah" is a word uttered by someone who is being overtly praised in an expression of grace and humility. In a similar fashion, yet in the opposite situation, if someone is verbally degrading themselves in front of others then the people in their surroundings will mutter "estağfurullah" to say, "don't say that," or "that's not the case." For example, if someone were to throw out the statement, "I am so stupid," then just as quickly someone in the vicinity will politely say "estağfurullah" in a lower voice as the way the word comes out also dictates.
"Hakkını helal et" is a loaded term that literally means to give up something to somebody that is rightfully yours, but when used it is asked as a sort of blessing. For example, if you overpay a taxi, the driver may turn and say to you, "hakkını helal et," in which you would nod in affirmation that you are aware and handing it over willingly. The same would be true if you gave someone something of disproportionate value or basically any situation in which your rights have somehow been infringed upon. It is a request for the giver to renounce their rights and promise they will have no claims against the taker in the divine court. It can therefore be a sort of apology in which you clear the air and tends to come at the end of a conversation. The responder replies by saying "helal olsun," meaning they have forgiven and relinquished their hold on whatever the exchange involved. "Helal olsun" with the inflection of an exclamation mark can also mean "well done" or "good job" in an enthusiastic show of approval.
"Kader" and "kismet" are two very special words in the Turkish language.
"Kismet" actually has a place in English meaning "fate," whereas in Turkish, "kader" means "fate" and "kismet" is sort of "destiny" or, in other words, the predestined lot. Turks believe that much of what transpires is predetermined by a supreme power, "yazılmış" as it were, which in Turkish means that "it has been written." One of the perspectives here I have always appreciated is when Turks say "yazılmış" in reference to the loss of a loved one, meaning that this particular fate was predetermined and therefore unavoidable, which sort of lifts the burden by leaving us powerless in the face of divine intervention.