The plural form of the word signal is signals.
Yes, there is a plural form for the word communication that can be used correctly; examples: Communications with the home office are temporarily out of order. We've received a number of communications from the Smiths on their world cruise.
The word messenger's is the possessive form for the noun messenger, for example the messenger's bicycle. The plural possessive form is messengers'.
signal
The plural form of connection is connections.
The plural form for fax is faxes.The plural possessive is faxes'.
The plural form for the demonstrative pronoun this is these.
The plural form of the word inferno is infernos.
The plural form is ranches.
There is no plural word for if.
There is no plural form for the word, countries. This word itself is a plural.
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.
There is no 'plural form' of the word 'minute'. The word is both singular and plural.
The plural form for the noun valley is valleys.