Why the th sounds are worth your time
Many learners believe th is very hard. For Arabic speakers there is good news: Modern Standard Arabic already has two similar sounds, ث as in «ثلاثة» and ذ as in «ذهب». The problem is that some Arabic dialects say s, z, t or d instead. Learners then carry that habit into English and say sink for think, or zis for this. People may still understand you from context, but sometimes the word changes completely, and your message gets harder to follow.
Two sounds, one spelling
The letters th stand for two different sounds in English:
- Voiceless th (no vibration in your throat), similar to ث: think, three, thank, thing, month.
- Voiced th (with vibration), similar to ذ: this, that, they, mother, brother.
Put your hand on your throat to feel the difference. In think you feel nothing at the start. In this you feel a buzz. Most short grammar words use the voiced sound: the, this, that, these, those, them, then, there, they.
Mouth steps for the voiceless th
- Relax your mouth and open it slightly.
- Put the tip of your tongue between your front teeth, or just behind the edge of the upper teeth. Do not bite it hard.
- Push soft air over the tongue. You should hear gentle friction.
- Do not use your voice. It is air only.
- Pull the tongue back quickly and finish the word: think, three, thank you.
If you can say Arabic ث clearly, you already know this position. You only need to use it in English words instead of s.
Mouth steps for the voiced th
The position is exactly the same. Just add voice:
- Place your tongue between your teeth as before.
- Turn on your voice, as if you were saying ذ, and feel the buzz with your hand on your throat.
- Let air flow over the tongue while the voice continues.
- Link it quickly to the next sound: this, mother, they.
In the sentence This is my brother. the voiced th appears twice. Say it slowly, then at normal speed.
th or s: word pairs
For s, the tongue stays behind the upper teeth and does not come out. The teeth are close together and air escapes through a narrow channel. For voiceless th, the tongue is in front of or between the teeth. Say each word on its own:
| th | s |
|---|---|
| think (use your mind) | sink (a kitchen basin, or go under water) |
| thank (say thanks) | sank (went under water) |
| thing (an object) | sing (make music with your voice) |
| thin (not fat) | sin (a wrong act) |
| mouth (noun) | mouse (small animal) |
Notice that th comes at the end of mouth and s at the end of mouse. Feel how your tongue moves differently in each word.
th or z, d and t
Some learners replace the voiced th with z or d. These pairs will help:
| voiced th | z or d |
|---|---|
| breathe (take air in and out) | breeze (a soft wind) |
| they (those people) | day (24 hours) |
| then (after that) | den (an animal home) |
| though (even if) | dough (bread mixture) |
Another common mix-up is voiceless th with t: three and tree, thank and tank. For t, the tongue touches the ridge behind the upper teeth and stops the air for a moment. For th, the air keeps flowing.
Common mistakes and corrections
| Common mistake | Correct form | Reason |
|---|---|---|
| I sink so. | I think so. | s used for th |
| Zis is my friend. | This is my friend. | z used for voiced th |
| I have tree brothers. | I have three brothers. | t used for th |
| Dank you. | Thank you. | d used for th |
| Fank you. | Thank you. | f used for th |
A useful rule: if your tongue never appears while you speak, you probably did not say th.
Sentences to say aloud
Read these slowly. Decide whether each th is voiceless or voiced:
- Thank you for this gift.
- I think that is the third door.
- They are with my brother on Thursday.
- My mother is thirty years old.
- Both of them like this month.
A British and American note: the subject is called maths in British English and math in American English. In both, th is voiceless.
A short daily routine
Give it five minutes a day. First, say th alone ten times in front of a mirror and watch your tongue. Next, say one word pair, such as think and sink. Then read one sentence from the list above. Record your voice on your phone and compare it with an audio dictionary. Short, regular practice works better than one long session now and then. Do not worry if the sound is not perfect at first; feeling the tongue position is the first step.