Why is it "hizmet" and not "hizmeti"? I'm still a little foggy on when the "the" suffix is needed and when it's not
The best thing to do first is to forget that there is a "the" suffix. There is no such thing in Turkish. There is a suffix for specific direct objects. "service" in this sentence is the subject, so it must be in nominative case. :)
"The service is very bad in this restaurant."
Translation: Bu restoranda hizmet çok kötü.
Bu restoranda servis çok kötü. - Correct.
When do you use restoranda and when lokantada please?
i thought that 'this' referıng to a specific restaurant would need a suffix
If it's the object of a verb.
Here, there is no object, and "in this restaurant" is just a prepositional phrase, so the noun is not in the accusative -- instead, it's in the locative, to express "in".
I had the feeling that 'restoranda' required 'ki'. Is it wrong to have it here or unnecessary?
It could be. It isn't required here though. It depends if you are wanting to say "(the service in this restaurant) is very bad" or something more like "(in this restaurant) (the service) is very bad."
Thanks! I think I get it now.
Would be Hizmet çok kötü bu restoranda be correct and if not, why?