The major difference between the two is the tongue.

To practice saying /θ/, stick your tongue out and move the air through your teeth. But for /s/ we move the air out through our teeth without sticking out our tongue.

So;

/θ/ tongue out/ air through teeth

/S/ tongue in/ air through teeth

Now keep practicing by saying these word pairs:

sing … thing

face … faith

force … fourth

sick … thick

sink … think

tense … tenth

mass … math

miss … myth

pass … path

saw … thaw

seem … theme

some … thumb

song … thong

use (n)… youth

worse … worth

gross … growth

seam … theme

sigh … thigh

sin … thin

sought … thought

sum … thumb

sank … thank

https://ieltsjuice.com/113-difference-between-sounds-of-th-and-s/

Alex: Hey, quick question. How do you pronounce "terrace," "tiramisu," and "terrorist"? I always get confused between those.

Jamie: Oh, I can see how those might be tricky! "Terrace" is pronounced "TEH-ress" — emphasis on the first syllable, and the "a" is like in "cat."

Alex: Got it! What about "tiramisu"?

Jamie: "Tiramisu" is "teer-ah-mee-SOO" — the "ti" sounds like "tea," and the "u" at the end is pronounced "oo."

Alex: And "terrorist"?

Jamie: For "terrorist," it’s "TER-or-ist" — the "er" is pronounced like the "er" in "her," with emphasis on the first syllable.

Alex: So, it's mostly about where you put the stress, right?

Jamie: Exactly! Stressing the right syllable makes all the difference.

1. Consonant to Vowel Linking

When a word ending in a consonant sound is followed by a word beginning with a vowel sound, the consonant "links" to the vowel.

• Example:

  • Take it → /teɪkɪt/

  • Come on → /kʌmɒn/

  • Turn off → /tɜrnɒf/

  • Put it on → /pʊtɪtɒn/

  • Leave it → /liːvɪt/

2. Vowel to Vowel Linking

When one word ends in a vowel sound and the next word starts with a vowel sound, we often insert a slight consonant sound like /j/ (y sound) or /w/ (w sound) to make the transition smoother.

• Example:

  • I am → /aɪjæm/

  • Go on → /goʊwɒn/

  • She is → /ʃiːjɪz/

  • Do it → /duːwɪt/

  • Blue eyes → /bluːwaɪz/

3. Consonant to Consonant Linking (Elision)

When a word ends in a consonant sound and the next word starts with the same consonant sound, one of the sounds is often dropped.

• Example:

  • Big game → /bɪɡeɪm/ (The /g/ in "big" is barely pronounced)

  • Fast train → /fæstreɪn/

  • Last time → /læstaɪm/

  • Next stop → /nɛkstop/

  • Red door → /rɛdɔr/

4. Intrusive 'R' Linking

When a word ends in a vowel sound (especially /ɑː/, /ɔː/, or /ɪə/) and the next word begins with a vowel sound, native speakers often add an /r/ sound to link them.

• Example:

  • Law and order → /lɔːrənɔːdə/

  • Idea of → /aɪˈdɪərɒv/

  • Asia is → /ˈeɪʒərɪz/

  • Saw it → /sɔːrɪt/

  • The media are → /ðəˈmiːdiərɑː/

5. Linking with 'H' Sound

When a word begins with an /h/ sound (e.g., he, his, her), this /h/ sound is often dropped in fast speech, and the vowel before it links to the following vowel sound.

• Example:

  • Tell him → /telɪm/

  • I saw her → /aɪ sɔːə/

  • Give him → /ɡɪvɪm/

  • Ask her → /æskə/

  • Show her → /ʃəʊə/

6. T to Y Sound (Assimilation)

When a word ending in a /t/ sound is followed by a word beginning with a /j/ sound, like "you," the two sounds blend together to form a /ʧ/ sound.

• Example:

  • What you → /wʌʧu/

  • Don’t you → /dəʊnʧu/

  • Got you → /ɡɒʧu/

  • Meet you → /miːʧu/

  • Can’t you → /kæːnʧu/

7. D to Y Sound (Assimilation)

When a word ending in a /d/ sound is followed by a word beginning with a /j/ sound (as in "you"), the sounds blend to form a /ʤ/ sound.

• Example:

  • Did you → /dɪʤu/

  • Could you → /kʊʤu/

  • Would you → /wʊʤu/

  • Should you → /ʃʊʤu/

  • Had you → /hæʤu/

8. Dropped 'T' or 'D' in Fast Speech

Sometimes in fast, casual speech, the /t/ or /d/ sounds are dropped, especially in phrases like "next door" or "I don’t know."

• Example:

  • I don’t know → /aɪdənoʊ/

  • Next door → /nɛksdɔr/

  • Just now → /ʤəsnaʊ/

  • I want to → /aɪwɑnə/

  • Kind of → /kaɪnə/

These linking sounds help make English sound more fluid and natural when speaking.

Tongue twisters are a great way to practice and improve pronunciation and fluency. They can also help to improve accents by using alliteration, which is the repetition of one sound. They’re not just for kids, but are also used by actors, politicians, and public speakers who want to sound clear when speaking. Below, you will find some of the most popular English tongue twisters. Say them as quickly as you can. If you can master them, you will be a much more confident speaker.

1. Peter Piper picked a peck of pickled peppers.
   A peck of pickled peppers Peter Piper picked.
   If Peter Piper picked a peck of pickled peppers,
   Where’s the peck of pickled peppers Peter Piper picked?

2. Betty Botter bought some butter
   But she said the butter’s bitter
   If I put it in my batter, it will make my batter bitter
   But a bit of better butter will make my batter better
   So ‘twas better Betty Botter bought a bit of better butter

3. How much wood would a woodchuck chuck if a woodchuck could chuck wood?
   He would chuck, he would, as much as he could, and chuck as much wood
   As a woodchuck would if a woodchuck could chuck wood

4. She sells seashells by the seashore.

5. How can a clam cram in a clean cream can?

6. I scream, you scream, we all scream for ice cream.

7. I saw Susie sitting in a shoeshine shop.

8. Susie works in a shoeshine shop. Where she shines she sits, and where she sits she shines.

9. Fuzzy Wuzzy was a bear. Fuzzy Wuzzy had no hair. Fuzzy Wuzzy wasn’t fuzzy, was he?

10. Can you can a can as a canner can can a can?

11. I have got a date at a quarter to eight; I’ll see you at the gate, so don’t be late.

12. You know New York, you need New York, you know you need unique New York.

13. I saw a kitten eating chicken in the kitchen.

14. If a dog chews shoes, whose shoes does he choose?

15. I thought I thought of thinking of thanking you.

16. I wish to wash my Irish wristwatch.

17. Near an ear, a nearer ear, a nearly eerie ear.

18. Eddie edited it.

19. Willie’s really weary.

20. A big black bear sat on a big black rug.

21. Tom threw Tim three thumbtacks.

22. He threw three free throws.

23. Nine nice night nurses nursing nicely.

24. So, this is the sushi chef.

25. Four fine fresh fish for you.

26. Wayne went to wales to watch walruses.

27. Six sticky skeletons. (x3)

28. Which witch is which? (x3)

29. Snap crackle pop. (x3)

30. Flash message. (x3)

31. Red Buick, blue Buick. (x3)

32. Red lorry, yellow lorry. (x3)

33. Thin sticks, thick bricks. (x3)

34. Stupid superstition. (x3)

35. Eleven benevolent elephants. (x3)

36. Two tried and true tridents. (x3)

37. Rolling red wagons. (x3)

38. Black back bat. (x3)

39. She sees cheese. (x3)

40. Truly rural. (x3)

41. Good blood, bad blood. (x3)

42. Pre-shrunk silk shirts. (x3)

43. Ed had edited it. (x3)

44. We surely shall see the sun shine soon.

45. Which wristwatches are Swiss wristwatches?

46. Fred fed Ted bread, and Ted fed Fred bread.

47. I slit the sheet, the sheet I slit, and on the slitted sheet I sit.

48. A skunk sat on a stump and thunk the stump stunk, but the stump thunk the skunk stunk.

49. Lesser leather never weathered wetter weather better.

50. Of all the vids I’ve ever viewed, I’ve never viewed a vid as valued as Alex’s vid.

www.engvid.com/english-resource/50-tongue-twisters-improve-pronunciation/ 

Here’s a list of minimal pairs that focus on vowel and consonant sounds in English, which can help with pronunciation practice:

Vowel Minimal Pairs

1. bit - beat

2. pen - pan

3. ship - sheep

4. cot - cat

5. full - fool

6. bed - bad

7. pull - pall

8. mat - met

9. cup - cape

10. hot - hat

Consonant Minimal Pairs

1. bat - pat

2. sip - zip

3. fan - van

4. lip - rip

5. cap - gap

6. sit - hit

7. sue - zoo

8. tall - call

9. ring - wing

10. bark - park

Mixed Vowel and Consonant Minimal Pairs

1. seal - zeal

2. right - light

3. coat - goat

4. bake - make

5. fine - vine