Place your tongue tip near the roof of your mouth behind your top teeth. Push air through the narrow gap. No voicing.

Americans pronounce seem as SEEM (/sim/). You'll hear it in sentences like "Most people seem to agree on this".
Record yourself saying "seem" and play it back. The mic stays on your device — nothing's uploaded.
1 syllable, 3 sounds. Explore each sound's mouth shape and how it's made.
Place your tongue tip near the roof of your mouth behind your top teeth. Push air through the narrow gap. No voicing.

Pull the corners of your lips back slightly. Arch the middle-front of your tongue high toward the roof of the mouth.

Press your lips together. Air flows through your nose. Vocal cords vibrate.
