When we hear /t/, we could be hearing sounds that are quite different. In English, the differences do not change the meaning of the words the way the difference between ‘b’ and ‘p’ would change the meaning of the words. In some languages, the same differences would change the meaning of the words.
This will be a chance to look at one phoneme and its associated allophones carefully and learn a few of the symbols of the IPA.
Consider the following four words:
Clearly, each of them has the letter ‘t’ and the sound ‘t.’ You can guess, that though they appear to be the same sound, they aren’t. Here’s how they are represented in the IPA.
The symbols are mysterious, at this point, but I am going to go over them.
First off, some of them are ones you know. ‘d,’ ‘s,’ ‘w,’ ‘k,’ and ‘n.’ are pretty much the way expect them to be. Vowels, the subject of the next section, are tricky because there are far more vowels in English than there are letters to represent them. In these 4 words, there are 5 of them (6, if you count, ‘r’ … I’ll get to that).
The symbol [ɛ] is the Greek letter Epsilon and is the ‘e’ sound in “bed.” So, if you forget about the weird ‘h’ superscript, you can see how [tʰɛd] would sound like “ted.”
The lower case ‘I’ is the sound ‘ee’ as in “bee,” so it is easy to see why [stɛdi] would sound like “steady.” Using ‘I’ for an ‘ee’ sound is common in many languages in the world.
The symbol [ɑ], is the Greek letter Alpha, and is the ‘a’ sound in “father.” The symbol at the end of “water” stands for “r.” ‘R’ is a complicated sound and there is a whole subsection on it coming up, but it can act as a vowel, and that’s what it’s doing here. For now, just realize that is the sound like the ‘r’ in “bird” or at the end of “water,” approximately, ‘err.”
The tricky part of the word “water” is the ‘t,’ which is not a ‘t’ sound by a sound called an alveolar-flap. I will get into this more in the section on consonants, but the sound is made by quickly flapping your tongue to the roof of you mouth just behind your teeth. The symbol for it looks like a lower-case ‘r,’ but it is smooth and does not have a column on the left [ɾ]. The next word, “kitten” uses the same sound. It can sound closer to a ‘d’ than to a ‘t.’
This is the same sound in the Spanish word “pero” (“but”) and the English words, “latter” and “ladder.”
The small capital ‘I’ [ɪ], is the ‘I’ sound in “bit” and “kit.” However, in the word “kitten” there is no [t]. It is [kɪɾ], followed by [ʔn̩]. You have seen the [ɾ], but the [ʔn̩] is mysterious.[ʔ] is called a “glottal stop.” It a consonant that is made by stopping the air with your throat (see the drawing in the section on Consonants). It is a common sound in English, but it usually does not change the meaning. Say “kitten” and feel how your throat closes just before the ‘n.’
One more thing about this word is the ‘n.’ Notice that there is a dot underneath it. This is a notation that means “the n is a vowel in this circumstance.” We will look into this in detail in the section on Sonorants coming up, but just be aware that that’s a possibility.
The last thing in this analysis is the ‘h’ superscript that I deferred above.
That refers to what is called aspiration which means that a little puff of air comes out after the consonant. Whether the puff of air comes out does not change the meaning of the word, that’s why ‘t’ with a puff of air and ‘t’ without a puff of air are both allophones of /t/. They are variations of the same phoneme.
You can test this for yourself by putting your hand right in front of your mouth and saying “ted.” You will feel a puff of air. Then say “steady” and you will not feel one. You can make a puff of air when you say “steady” and it will not change the meaning of the word. However in some languages, like Chinese, Thai, Hindi, and many others, aspirated and unaspirated consonants are different phonemes and change the meaning, so, if they had the words [tɛd] and [tʰɛd], they would mean different things. [t] and [tʰ] would not be allophones, but different phonemes.
The next sections expand on the idea of contrasting sounds, go through the categories of sounds, list the allophones of the consonant phonemes, and then explore syllables, stress, words, phrases, sentence, and interactive speech, starting with vowels.