Can language be inclusive?

From your composition I've noticed that when you want to refer to man, woman, boy or girl in general you use the Catalan formula "he / she" or "the boy / the girl / the son / the daughter" and I've thought it could be interesting to let you know which is the English one. 

If we are referring to "he / she" we can use the plural pronoun "they". 
The "he / she" formula can also be written in the "s/he" form, which it's said to be more inclusive.

Can you please explain me what does the term "inclusive" mean?
Write down something inclusive  – not necessarily a pronoun —, think about whether it's relevant or not in our society, and take note in which cases this can be useful, for instance in the use of terms that describe people such as job titles.