Word stuck on the tip of your tongue? You already know its first letter and syllable count

Roger Brown and David McNeill gave students definitions of rare words and asked them to name the target. When stuck, people could reliably guess the first letter, syllable count, and similar-sounding or similar-meaning words far above chance - showing a 'lost' word isn't gone from memory, just its full form is briefly out of reach.

— Roger Brown and David McNeill, The 'Tip of the Tongue' Phenomenon — Journal of Verbal Learning and Verbal Behavior, 1966