As I understand it, this book advocates anchor tonguing: placing the tip of the tongue behind the lower teeth and tonguing with the middle of the tongue. It makes no sense to me: how does anchoring the tip of the tongue do anything except slow it down? Arnold Jacobs said tongues come in different lengths and widths, so perhaps anchoring tongue helps deal with a long tongue? I read that Herbert Clarke could anchor tongue or use regular tonguing with equal success. Since he was probably the greatest cornet player of his day, it’s no surprise that he could do things that most people can’t.
Another thought — Arnold Jacobs said the tongue is the most complex part of the body and is controlled by muscles in the tongue and around the tongue. He said the best way to deal with the tongue is through diction, not mechanics. (He studied to be an opera singer but developed nodes on his vocal chords, which ended his career. This vocal training probably gave him a unique perspective on the tongue.) Anyway, how many people talk with their tongue anchored?? Probably none, so why would we tongue like that when we play a brass instrument??
Seeing this kind of information circle around the net makes me think people are looking for the magic secret that will make playing easy without much practice or it is what the best players have always done, but it was a closely guarded secret. No chance of that — musicians are much too generous trying to help each other for anything to stay a secret for long.
Besides, if this technique was so successful, why didn’t it catch on?? Ligner’s book was written about 140 years ago, more recent than Arban’s hugely successful method, not 3,000 years ago. I don’t see this technique as likely to have been lost in the sands of times; more likely, it didn’t work for most folks and was abandoned.
Spending time on this technique would be better spent practicing to improve what a player has always done.
A review of the book is available on the Wayback Machine: Ligner, 50 Exercises: Sur Le Coup de Langue Ternaire