The content of App. E of LOTR is condensed. All tengwar have a "full name" in Quenya. Tolkien wrote:
"Each ‘full name’ was an actual word in Quenya that contained the letter in question. Where possible it was the first sound of the word; but where the sound or the combination expressed did not occur initially it followed immediately after an initial vowel."
So where is the tengwa anna in the full name anna? Nowhere! It should have been written by Tolkien: ’anna or ȝanna.