How to produce /θ/ and /ð/, common errors, and practice activities
Sound Symbol
/θ/ and /ð/
Typical Development
5-7 years
Expected Mastery
6-7 years
English has two TH sounds: voiceless TH (as in 'think') and voiced TH (as in 'the'). Both require placing the tongue between or just behind the teeth—a position unique among English sounds. TH sounds typically develop between ages 5-7 and are among the last sounds mastered. Many children substitute F, D, or V for TH well into school age.
Tongue tip is placed between the upper and lower front teeth, or just behind the upper teeth with the tip visible. It sticks out slightly.
Lips are relaxed and open, allowing the tongue to protrude slightly.
Upper teeth rest gently on the tongue. There's visible space between top and bottom teeth.
Air flows over the tongue, creating friction. Voiceless TH (think) has no vibration; voiced TH (the) has vocal cord vibration.
The most common substitution. The tongue stays behind the teeth like F instead of protruding.
Common in young children. The tongue touches fully behind the teeth, stopping airflow like D.
The tongue stays behind teeth and lips create the sound, similar to the F/TH confusion.
Less common, but some children produce S instead, especially if they have a frontal lisp.
TH Sound at the beginning
TH Sound in the middle
TH Sound at the end
Try these activities at home to help your child practice the TH Sound.
Practice sticking the tongue out just a tiny bit and biting down gently. Say 'thhhh' while looking in a mirror to see the tongue peeking out.
Make funny faces with the tongue sticking out, then add sound: 'Thhhhhh!' Make it a game to help reduce self-consciousness.
Say pairs like 'thumb/fun' and 'three/free.' Feel the difference: tongue out for TH, lip touches teeth for F.
Count objects using TH words: 'three things, thank you!' The repetition builds muscle memory.
Consider a speech-language evaluation if:
TH sounds typically develop between ages 5-7, with mastery expected by age 7-8. Many kindergarteners and first graders still substitute F or D for TH, and this is developmentally appropriate. If errors persist past age 7-8, therapy can help.
English has voiceless TH (as in 'think'—no vocal cord vibration) and voiced TH (as in 'the'—vocal cords vibrate). Both use the same tongue position. Children often master one before the other, typically voiceless TH first.
No, F for TH substitution is not a lisp. It's a common developmental error where the tongue stays behind the teeth (like F) instead of protruding (for TH). A lisp specifically refers to S and Z sound errors.
TH sounds are unique to English and don't exist in most other languages. Children learning multiple languages may take longer to master TH, especially if their other language doesn't have this sound. This is normal for bilingual development.
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