The English "th"
The two letters t and h in combination (th) are very common in English. They represent one of two different sounds:
- the voiced dental fricative /ð/ (as in this)
- the voiceless dental fricative /θ/ (as in thing)
The sound /ð/ has the following features:
- Its manner of articulation is fricative. That means the sound is produced by letting air flow through a narrow channel at the place of articulation.
- Its place of articulation is dental. That means the sound is articulated with the tip of the tongue against the back of the upper teeth.
- Its phonation is voiced. That means the vocal cords vibrate during the articulation.
Speak the voiced th /ð/ out loud several times, according to the features above: put the tip of your tongue against the back of your upper teeth, produce a little air flow and let your vocal cords vibrate. Listen to the audio file to hear how it is supposed to sound.
Now practise the sound by pronouncing words that start with it: the, this, those, their, then. Then listen to the audio file below.
The second variation of th, the sound /θ/, has the following features:
- Its manner of articulation is also fricative. That means the sound is produced by letting air flow through a narrow channel at the place of articulation. In comparison to the voiced th, the voiceless th is pronounced by making more air flow.
- Its place of articulation is dental. However, in contrast to /ð/, the sound is pronounced with the blade of the tongue resting against the lower part of the back of the upper teeth. The tip of the tongue sticks out of the mouth slightly.
- Its phonation is voiceless. That means the sound is produced without vibrations of the vocal cords.
Now, speak the voiceless th /θ/ out loud several times, according to the features above: put the blade of your tongue against the lower part of the back of your upper teeth and produce an air flow. Do not let your vocal cords vibrate. Listen to the audio file to hear how it is supposed to sound.
Now practise the sound by pronouncing words that start with it: thing, thought, through, thorough, threat. Then listen to the audio file below.
Practise the two sounds /θ/ and /ð/ in turn. Pronounce the one, then the other and repeat this a few times. Pay attention to the differences in their pronunciation. Then, hold a hand a few centimeters in front of your mouth and notice the differing force of the puff of air that you are producing. You can listen to the audio file below.
Listen to the audio file below. Many words containing th are pronounced. Try to notice which of the two sounds, /ð/ or /θ/, is used in which words:
- Use the yellow colour to mark the words containing the voiced /ð/ sound by first clicking on the yellow area and then on the respective words.
- Then use the blue colour to mark the words containing the voiceless /θ/ sound by first clicking on the blue area and then on the respective words.
There are no rules about when a word contains either a voiced th sound or a voiceless th sound.
However, there are certain regularities that may help you. They can be categorised into three groups: th at the beginning of a word, th in the middle of a word and th at the end of a word.
1. Th at the beginning of a word:
- In almost any case, the th is a voiceless /θ/ as in threat, thought, think, throw, ….
- Function words usually begin with the voiced /ð/ as the pronouns they, them, their, the, this, that, these, those and the adverbs and conjunctions then, there, than, thus, though, therefore, therbey, thereafter, ….
2. Th in the middle of a word:
- Most English words have a voiced /ð/ in the middle, when there is a th, as in either, father, mother, brother, rather, further, together, weather, whether, ….
- Most loan words have a voiceless /θ/ in the middle, when there is a th, as in cathedral, enthusiasm, ethics, mathematics, lethal, method, mythical, ….
3. Th at the end of a word:
- Nouns and adjectives usually end in a voiceless /θ/, when there is a th, as in bath, cloth, breath, tooth, teeth, ….
- Verbs usually end in a voiced /ð/, when there is a th, as in breathe, loathe, soothe, writhe, ….