/ð/

Place the tip of your tongue lightly between your upper and lower front teeth. Your tongue should gently touch the edges of your upper teeth or peek out just slightly between them.

Now push air through this narrow gap while turning on your voice - your vocal cords should vibrate. You'll feel a buzzing sensation in your throat and a slight vibration where your tongue meets your teeth.

The key difference from the voiceless "th" (as in "think") is the voicing. Keep your tongue in the same position, but add that vibration.

Many learners substitute /ð/ with:

• /d/ - "the" becomes "de," "brother" becomes "brudder"
• /z/ - "this" becomes "zis"

The /d/ sound stops the airflow completely (your tongue touches the roof of your mouth), while /ð/ lets air flow continuously through the gap between your teeth.

The voiced "th" appears in many common words:

• Function words: the, this, that, these, those, they, them, there, then
• Middle of words: mother, brother, father, weather, together
• End of words: breathe, bathe, smooth

Place two fingers gently on your throat while saying "zzzzz" - feel that vibration? Now keep that buzzing going, open your mouth slightly wider, and slide your tongue forward between your teeth. The vibration should continue. If it stops, you've switched to the voiceless /θ/.

Practice the contrast: "the" (voiced /ð/) vs. "think" (voiceless /θ/). Your throat vibrates for "the" but stays quiet for "think."