Allah is a proper name. But in Turkish it also has so many uses in conversational phrases and sayings (allah allah, allahtan, allahın aşkına, inşallah, maşallah, allaha emanet ol). What is the correct spelling of these phrases? Should we use the capital letter and the apostrophe in writing?

Allah Allah

Allah´tan

Allah aşkına

inşallah

maşallah

Allah´a emanet ol.

Writing "Allah" without capital letter is disrespectful. But you can write "inşallah" and "maşallah" without capital letter if the sentence doesn´t start with them.

A very good question in fact my favorite one. So i would like to tell you ALLAH is the name of a lord of whole universe , as we all know.all the creatures including human being obey to him.It is necessary to write  the name of ALLAH in the capital letters. ALLAH is a proper name no doubt we should respect this name by heart.We should follow the QURAN for the proper pronounciation and properly to write the name "While using in conversation"

inşhallah is to be write as In sha ALLAH

maşallah is to be write as MashALLAH.

ALLAHa is to be write as ALLAH only.

ALLAH´s name must be in capital leters always.

While no apostroph is necessary to put. 

In Turkish I have never seen inşAllah or maşAllah. The grammar of the language doesn´t allow it.

oh it means just because of grammer u will direspect the name ALLAH. strange !!

No it is not disrespectful when the way of writing is like that. Do you think all Turkish Muslims write it that way to disrespect Allah?

it Should be in capital letters by all means. you are not writing the name of any ordinary person . This is the name of ALLAH Almighty who is the master of every thing

grammar ... 

thank you nemanja for coorecting my mistake

İnşallah is one word in Turkish. Turkish is different than Arabic. It is not disrespectful. If it was, Turkish Muslim scholars would object it.