English has two sounds that most Romance language speakers find extremely difficult: the voiceless TH /θ/ (as in "think") and the voiced TH /ð/ (as in "this"). Neither sound exists in Portuguese or French, and only one appears in certain varieties of Spanish.
What makes these sounds especially tricky is that speakers of each language substitute them with different sounds. A Spanish speaker might say "dis" for "this", while a French speaker might say "zis", and a Portuguese speaker might say "fink" for "think". Understanding your specific substitution pattern is the key to fixing it.
What Are the Two TH Sounds?
Both TH sounds are dental fricatives, meaning the tongue touches or comes near the teeth while air flows continuously.
- /θ/ (voiceless): No vocal cord vibration. Examples: think, three, bath, tooth, author
- /ð/ (voiced): Vocal cords vibrate. Examples: this, that, breathe, father, weather
Tongue Position for Both Sounds
Place the tip of your tongue between your upper and lower teeth, or lightly touch the back of your upper teeth. Then blow air gently. For /ð/, add voice (vibrate your vocal cords). For /θ/, keep it voiceless (just air).
How Spanish Speakers Substitute TH
Spanish speakers typically make these substitutions:
- /θ/ becomes /t/ or /s/: "think" becomes "tink" or "sink"
- /ð/ becomes /d/: "this" becomes "dis", "that" becomes "dat"
Interestingly, many Spanish speakers already produce a sound very close to /ð/ without realizing it. In casual speech, the Spanish "d" between vowels (as in "cada" or "todo") is actually pronounced as the fricative [ð], not as a hard [d]. If you can isolate that soft "d" sound, you already know how to make /ð/.
For /θ/, speakers from central and northern Spain have an advantage: the Spanish "z" (as in "zapato") and "c" before "e" or "i" (as in "cielo") are pronounced exactly as /θ/ in Castilian Spanish.
How Portuguese Speakers Substitute TH
Portuguese speakers tend to make different substitutions:
- /θ/ becomes /f/ or /t/: "think" becomes "fink" or "tink", "three" becomes "free"
- /ð/ becomes /d/ or /v/: "this" becomes "dis", "brother" becomes "brover"
The /f/ substitution for /θ/ is particularly common among Brazilian Portuguese speakers. This is because both /f/ and /θ/ are voiceless fricatives, and the lip position for /f/ feels more natural. The key difference: for /f/ the lower lip touches the upper teeth, but for /θ/ the tongue touches the upper teeth.
How French Speakers Substitute TH
French speakers have a distinctive pattern:
- /θ/ becomes /s/ or /f/: "think" becomes "sink" or "fink", "math" becomes "mass"
- /ð/ becomes /z/ or /d/: "this" becomes "zis", "that" becomes "zat"
The /s/ and /z/ substitutions are the most common for French speakers. This happens because French has strong /s/ and /z/ sounds, and they are the closest French fricatives to /θ/ and /ð/. The problem is that /s/ and /z/ are alveolar (tongue behind teeth), while /θ/ and /ð/ are dental (tongue between teeth).
Common Substitution Patterns Compared
| English Sound | Spanish Substitution | Portuguese Substitution | French Substitution |
|---|---|---|---|
| /θ/ (think) | /t/ or /s/ | /f/ or /t/ | /s/ or /f/ |
| /ð/ (this) | /d/ | /d/ or /v/ | /z/ or /d/ |
Practice Words: Voiceless /θ/
Start with these common words. Focus on placing your tongue between your teeth and blowing air without vibrating your vocal cords.
Practice Words: Voiced /ð/
Now try these words. Same tongue position, but this time vibrate your vocal cords. You should feel a buzzing in your throat.
The Mirror Test
Here is a simple self-test: stand in front of a mirror and say the word "think". Can you see the tip of your tongue between your teeth? If not, you are probably substituting with /t/, /s/, or /f/. Your tongue must be visible between your teeth for a correct TH sound.
Minimal Pairs to Train Your Ear
These word pairs differ only in the TH sound versus its common substitution. Practice hearing and producing the difference.
For /θ/ vs /t/ (common for Spanish and Portuguese speakers)
- think /θɪŋk/ vs tink (not a word, but what it sounds like)
- three /θriː/ vs tree /triː/
- thick /θɪk/ vs tick /tɪk/
- bath /bæθ/ vs bat /bæt/
For /θ/ vs /f/ (common for Portuguese and French speakers)
- three /θriː/ vs free /friː/
- throw /θroʊ/ vs fro /froʊ/
- thought /θɑːt/ vs fought /fɑːt/
- thin /θɪn/ vs fin /fɪn/
For /ð/ vs /z/ (common for French speakers)
- then /ðɛn/ vs zen /zɛn/
- those /ðoʊz/ vs a lisped "zose"
- worthy /ˈwɜːrði/ vs something like "worzy"
Step-by-Step Practice Routine
- Isolation: Start by just saying "thhhh" with your tongue between your teeth. Hold the sound for 5 seconds, voiceless. Then add voice for /ð/.
- Simple words: Practice the word cards above, one at a time, slowly.
- Minimal pairs: Alternate between "three" and "tree", "think" and "tink". Exaggerate the tongue placement.
- Sentences: "I think that the weather is good" contains both /θ/ and /ð/. Say it slowly, then gradually speed up.
- Record yourself: Use a voice recorder and compare your pronunciation to a native speaker.
Key Takeaways
- Both /θ/ and /ð/ require the tongue to be between or touching the upper teeth.
- Spanish speakers: use your soft intervocalic "d" (as in "cada") for /ð/.
- Portuguese speakers: do not round your lips like /f/; keep them relaxed and push the tongue forward.
- French speakers: move your tongue forward from the /s/ or /z/ position until it touches the teeth.
- Practice with the mirror test to make sure your tongue is visible.