How easy can you interact with a person with disabilities ie deaf?

This is not easy if you do not speak sign language, everything has to be written down ... on a piece of paper or email ... body language can be used till you find a pen and paper .....

Hopefully sign language is an international used the same way... this would be actually helpful

Sign Language. However I would Suggest yoo Texting them in Phones. If not Write it down on a Paper. 

It's not usual scenario but incase you find a person with disabilities try to be most humble and use the best actions to communicate with a true smile and passion to such individual .

We can use sign language.

Written language online is easy

I would look for a paper and write or alternatively I would try to use body language to communicate to the person.

I would interact myself with them by writing my views in a paper or with a simple signs acting with my hands to understand the person or by texting them through messages

It is easy in the sense that you should put your shoes on them by knowing what kind of disablities do they posses. If deaf, Its better to use Writings on a piece of paper, instead of sign language which you are master & can only create confusions or maybe commotions in future due to misunderstanding.

through mediums of Writing on paper, texting, e-mail, 

but the most viable way is to have a person who is versatile in sign language.

I use sign language to communicate with them

use of sign language and writting words down. you can as well learn the different ways of communicating to the different abled

First there is equal apportunity policy so being deef or any other barrier to communicate will have no less treatment than anyone else.since most working places are equiped with special needs facilities that will be my first option if not will make sure to dedicate enough time to investigate and communicate through writing of other non verbal communcations to confirm needs and answer questions