Linguistics, The Difference Between Cat[s] and Dog[z]
What exactly is the difference between cats and dogz? The common answers come up quickly; Dogs slobber, Cats are clean, Dogs are friendly, Cats are more aloof.
Of course in a linguistics class nobody is going to guess that. Actually most kids will just sit there and wonder "What the heck is my teacher talking about?"
Because in the context of linguistics it is quite difficult to tell the difference between cats and dogz.
I gave you a hint already. Go ahead say them out loud. Cats. Dogz. Why am I spelling them that way? Can you tell anything?
If you say the word 'cats' out loud slowly and then follow it with Dogs out loud, you might hear the difference. Still don't hear anything? Place two fingers on your throat and try it again.
Pay close attention and you will notice that when you say the word "dogs" your throat vibrates a good amount on the "s" sound. When you say the word "cats" there is no vibration on the "s" sound.
Accompanying this vibration you'll realize that when you say dogs in context, you are actually pronouncing the plural sound "s" as a "z". Now say the sentence "I walked my dogs to the grocery store" and then replace 'dogs' with cats in the sentence "I walked my cats to the grocery store"
All native English speakers (this might not work if English is a second language for you) will be replacing that 's' sound with a 'z' but only on the dog.
So whats happening? Turns out there are certain rules in the English language (all languages have them) that affect the way certain sounds are pronounced. In this case English will change the 's' plural sound into a 'z' because the consonant preceding it is a voiced consonant.
A voiced consonant?
A voiced what?
A few observations to understand this more clearly:
All sounds have a few features that will distinguish them from one another. Otherwise all language would sound the same and we wouldn't be able to communicate!
One such feature is called "voicing". In the case of the sounds [s] and [z] it is the only feature that distinguishes them. Yep that's correct, the only difference between [s] and [z] is the feature voicing. You can tell this by doing a simple test. Go ahead and place those two fingers back on your throat. Now say out-loud (loudly! don't be shy) "ssssssss" and then change to "zzzzzzz"
You'll notice that the only thing changing between [s] and [z] is your vocal cords turning "on" and "off". [z] is voiced and [s] is voiceless.
So what? Well in the word cat the [t] at the end of 'cat' is also voiceless. In the word 'dog' the [g] at the end of 'dog' is voiced! So what does English do? When you have to add a plural sound to a word, English will actually always pick between one of two sounds: [s] or [z] and it will pick based whether or not the final sound of the base word is voiced or voiceless.
If you want to test out the theory just try it on some other words. Can you guess what the real sound of bags is? Or how about "hubs"? Is it really an [s] there?
If you still don't believe me try it with a made up word all together. Finish this sentence for me. "I had a Wug, then I got two Wug[?]"
What sound do you add to make a Wug plural? What about another made up word like "lup". "I had a lup, now I have two lup[?]"
Clearly the English language is a bit smarter than we realize. By alternating the sound used at the end of the word, we are saving ourselves the effort of having to “turn off” or “turn on” our vocal cords. This in turn increases the efficiency of English.