* sin diye  ---> so that he/she......

He is going to bed early so that he can get up early.

Actually,in that example it  sounds better if we use -eyim diye, although the person is 3th singular.

O, erken kalkayım diye erken yatıyor.

Unless we change the example using two different persons in one statement.

O, Ali erken kalksın diye saati kurdu.

He set the clock for Ali to get up early.

He set the clock so that Ali could get up early.

-Diye

The use of the word diye is quite common and it has many functions.

* .....diye sordu

- Kışlıkları sandığa kaldıralım mı ? diye sordu. 

She asked [saying] , "Shall we put the winter things in the trunk ? "

- " Nerede ? " diye sordu. 

 He/She asked [saying] where is he/she/it ?

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*......diye söyledi.[or other verbs]

direct quotation of a statement

- Yarın gelmeyeceğim diye söyledi. 

She said "I will not come tomorrow".

- Hayır diye haykırdı. 

She screamed, "No ! "

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* It can also be used to express what is being thought in someone´s mind. Sometimes this is done by using "....diye düşündü "

- " Ama param kalmadı " diye düşündü. 

 " But I don´t have any money left" he thought.

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* Sometimes the sentence itself makes it clear that the person´s reasoning or thinking is being expressed , without using the verb düşünmek.

- Onu gelecek diye bekliyordum.

 I was waiting for him to come.

- Değişiklik olsun diye otobüsle geldik.

- For a change, we came by bus.

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* Often it carries the meaning of purpose or reason :

-eyim diye ---> so that I ...

Bu resmi bitireyim diye kursa katıldım. 

I have enrolled in a course so that I can finish this painting.

* sin diye  ---> so that he/she......

He is going to bed early so that he can get up early.

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A few other uses :

.....diye bir şey yok  --------> Nothing like.........exists

mecbur olmak = to be obligated to / to have to do 

ona hesap vermeye mecbur değilsin - You don´t have to give him explanations.

Bana olan borcunu odemeye mecbursun. ---> You have to pay me your debt.

ona hesap vermen gerek ---> you need to give him explanations.

                                                   [should]

Bana olan borcunu odemelisin. --> you must pay me your debt.

 -dim  eli

This reduplicating form has the same meaning as the -eli form. It is a little more emphatic perhaps.

The past -di form of the verb is followed by the -eli form of the same verb. The second verb with the -eli does not change except for vowel harmony. Person is indicated by the ending of the verb with the -di ending.

bildim bileli  ----> ever since I´ve known

gittin gideli ---->  ever since you´ve gone

gitti gideli ----> ever since he went

sattık satalı ---> ever since we sold

- Onu bildim bileli böyledir. ---> He´s been like this ever since I´ve knownhim.

- Gitti gideli ondan bir haber almadık. ---> We´ve had no news of him ever since he left.

The modal of obligations in Turkish can be grouped in two category :

1) Lexical obligation

Gerek:

Gerek is one of the oldest existing modal in Turkish.

 Old forms were ‘kergek, kergeksiz, ne kergek ” in both verb and adjective forms.

Mutfağa bir masa gerekiyor.   -à The kitchen needs a table.

Gitmem  gerekiyor.  -à  I need to go.

Lazım :

This is borrowed from Arabic nearly from 13^th century. This word is used  for obligations..

Gitmem lazım. -à I must/ need to go.

Görmem lazım. -à I must / need to see.

Zorunda :

This word indicates just obligations/necessities.  It has been created in 20^th century New Turkish.

Gitmek zorundayım.  --à I have to go.

Durumunda :

       This word was quite newly created. Likewise , it indicates obligation.

       Gitmek  durumundayım.  -à I have to go.

     2)  Grammatical obligation

-        malı/meli  is the only suffix that denote obligation in Turkish. The formation of  -malıgoes back to the last period of  Old Anatolian Turkish era.  From participle –ma and suffix –lı  is combined by referring the future. First as participle and later in Ottoman times it started to appear as necessity/obligation suffix.

·       In contemporary Turkish, it may denote both necessity and advice/suggestion.

Bu filmi izlemelisin. --à You should watch this film. -à Suggestion.

Dersine çalışmalısın. -à You must/should study your lesson.  -à Necessity

Karnım aç. Birşeyler yemem lazım.

Birşeyler yemen lazım.

I need small room --> Bana küçük bir oda lazım.

However, Turks prefer to say " I want a small room". We don´t tend to use " I need", instead we say " I want "

Küçük bir oda istiyorum 

You can also say: 

"Tek kişilik bir oda istiyorum" if you want single room, or if it is room for two persons "Çift kişilik bir oda istiyorum."

I agree. The other difference between those two words are ; "konuk " is Turkish word whereas "misafir" is Arabic origin word. 

The root of  word comes from "sefer" = long walk, journey.

So, "müsafir " the person who makes long walk or journey / Passenger.

Complete the blanks in the sentences below:

1) Artık sinemaya  gitmiyorlar.

They don´t go to the movies any more.

2) Artık sinemaya  gitmez  oldular.

They stopped going to the movies.

3) Artık  sinemaya  gitmiyorlarmış.

Reportedly, they don´t go to the movies any more.

4) Artık  sinemaya  gitmeyecekler.

They won´t go to the movies any more.

Yes, they are more or less same. You can translate in both ways.

Artık sinemaya gitmeyi bıraktılar.

Artık sinemaya gitmez oldular.

More info on "-mez oldu " form  :

 maz/mez  Oldu  Form ;

With negative aorist tense [mAz] with oldu expresses the action,event ceased to happen.

        Verb stem + maz,mez + oldu + person

Sen gelmez oldun. ---> You stopped coming. [ You used to come but you stopped coming]

O artık bana selam vermez oldu ---> He/She stopped greeting [saying hello to] me.

Onlar bir süredir çay içmez oldular ---> They stopped drinking tea for a while.

Son zamanlarda birbirimizi görmez olduk ---> Lately , we, for some reason unable [stopped] to see eachother.