Lingual tonsils lie on the back of the tongue, low down, above the voice box. This area is called the retrolingual space. Blockage here will cause persistent snoring. Lingual tonsils can block this area, see picture. A diagnosis often missed. They can be treated with anti inflammatory medication or surgery.
Thick arrow is the retrolingual space.
Thin arrows are the lingual tonsils taking up retrolingual space.