The English plural adds the usual "s" as "barnyards".
Barnyards is already plural. The singular form is barnyard.
The plural form for the demonstrative pronoun this is these.
The plural form of the word inferno is infernos.
The plural form is ranches.
It is a common noun but it is not plural.
There is no plural form for the word, countries. This word itself is a plural.
There is no plural word for if.
The plural form is data.
The plural form of the word "baby" is "babies."
The plural form for the word 'pioneer' is pioneers.
The plural form of the word "pharynx" is "pharynges."
The plural form of vow is vows.