What 'd you do if you were auditing a company & found QMS docs, SOPs, forms, etc are in English although 80% of employees are speaking Arabic only?

There are certain rules defined. ISO emphasises on "Do What you say and Say What you do". No matter What language they speak, If they have translations or proper understanding of what is written in books, Its OK.

SOPs and Instructions must be complied. Take an example from my country Pakistan, We have people who speaks Urdu but we have translations of Quality Policy, SOP and Work Instructions displayed for common understanding of people. But if its not, an observation or suggestion may be raised instead of non-compliance provided the SOP and instructions are complied.

Documents either SOP or work instruction need to be available with the key persons , who are implementing process in the language of understanding. In rare cases translator can be used if auditor not able to communicate with auditee in english. 

Whenever changes happens and need new system implementation or modifcation than specal trainer in local language can be arranged to ensure correct understanding...

If the employees are doing what is written in the SOP and all the documents and forms are maintained, i dont see how this is a problem.

Its clear the SOP is communicated with the non english speakers and there is document controler/ keeper appointed to maintain the docs in english.

Audit should not be validized.