/s/

Position the tip of your tongue close to the alveolar ridge - that's the bumpy area just behind your upper front teeth. Don't touch it directly; leave a tiny gap to create a narrow channel. Your teeth should be close together (almost touching), and your lips slightly parted, almost like a gentle smile.

Now push air steadily through that narrow channel between your tongue and the roof of your mouth. The air rushing through this tight space creates the characteristic hissing sound of /s/.

Keep your vocal cords silent - there should be no vibration in your throat. If you feel buzzing, you're making /z/ instead.

These sounds are twins - same tongue position, same mouth shape. The only difference is voicing. For /s/, your throat is quiet. For /z/, your vocal cords vibrate.

Try this: say "ssss" and "zzzz" back and forth. Your mouth stays exactly the same, but you'll feel your throat turn on and off like a switch.

• Frontal lisp: Your tongue pokes between your teeth, making /s/ sound like "th." Keep your tongue behind your teeth.
• Lateral lisp: Air escapes over the sides of your tongue, creating a "slushy" sound. Press the sides of your tongue against your upper molars to seal the edges.
• Too much tension: A tight jaw or tongue can make /s/ sound harsh. Stay relaxed.

Hold your hand an inch in front of your mouth and say "ssss." You should feel a focused, narrow stream of cool air hitting your palm. If the airflow feels broad or you feel warmth, adjust your tongue position until you get that sharp, directed airstream.