"Bu durum karşısında Hoca bir şey söylemeden onları içeri alır ve sofraya oturtur."

Source; I think from Princeton University. (I think its a children´s story) I have been trying to practice translating, though maybe that interactive site has Turkish thats a bit advanced for me yet. But I thought I would try anyway! I mention my sources so you know I dıdn´t make the sentences.

Most of it has been ok, enough to get the gist of the sentences from the words and suffixes but probably not accurate translation. I came across that sentence.

I was able to understand most of the sentence but it made me wonder about "söylemeden" When you have the -den/-dan suffix after a verb, instead of a noun, how does that work? Or is there something I am missing? Is it still "didn´t tell"?

Thanks in advance and I may post more to the thread if I have more questions about this exercise. 

-meden means without. You have to add it to the root of the verb. It is not about -den, -dan. -meden is a different suffix. It makes verbs adverbs.

So, is "gel-meden önce" belongs to this structure???

I think so

that means before coming

But if we go by logic, i don´t think they are same...gok explained that it gives a meaning i.e without..and in this case there is no without...so may be are different forms...

It should be broken up as

gelme-den önce = before coming

not to be confused with -meden:

V+ -meden = without V+ing

Im not sure what you mean ,but yes they are different

one means without= meden (ing)

the other

meden önce= before (ing)

and

medikten sonra= after (ing)

I think

Thanks si... 

Thank you Gokuyum, Deli and Si+ so used in my example,

"birşey söylemeden" = "something without telling"

If this is part of adverbial clauses, do thy follow vowel harmony or no? Or is there -madan for a, ı, o, u ?

örn

sormeden= without asking

paylaşmeden=without sharing

 sormadan

paylaşmadan

they follow vowel harmony.

sarılmadan ---> ı ---> a       [ without hugging]

korumadan ---> u ---> a     [ without protecting]

koşmadan -----> o ---> a    [ without running ]