Hi everybody!!
It's been a long time since I visitted this forums last. My reagards and best wishes to you all. Please accept my good greetings to you all.

And here is my question
I would like to know if there is any spelling rules for the words below.

*Mix = Mixture
[why is a 'T' there in noun forms of the words above?]

Apologetical [Why is a 'T' their in the adjective form of apology]

why is is editoRIAL and not editoRAL?

Is there any rule to put a K for the 'ing' form?

Thank you
Not easy questions, Bubu, and I am only trying to answer some, because no one else has:

'Expenditure', my dictionary says, is irregularly formed from 'expend', so no reason beyond history of use is accessible.

'Mixture' has a 't' because it is derived from the Latin mixtus-- again from my dictionary.

'Apologetic' goes all the way back to Greek apologetikos.

'-Ial' and '-al' are two different forms of the same adjective suffix. 'Manorial', 'senatorial'-- '-ial' was probably chosen for its sonority with the preceding liquid 'r'.

'Panicking, picnicking'-- the 'k' is added to clarify that the 'c' represents the /k/ sound; this could be misinterpreted as /s/ in '*panicing' like /s/ in 'icing'.

There are likely more definitive answers to some of these questions, but it will take a Latin scholar to explain the noun and adjective declensions that often determine the precise forms of some of our English word constructions.
wow! What an answer !! Wish I was rich enough to send a $20 for that. Great answer Mr micawbwer. THANK YOU.