A noun appearing as Q. lapsa “gluttonous eating” in the Outline of Phonology (OP2) from the 1950s from primitive ✶labdā (PE19/91-92 note #110). It also appeared as ᴹQ. lapsa in Outline of Phonetic Development (OP1) from the 1930s with the glosses “licking up (food or drink), gluttonous eating”, the first of these presumably the original (archaic?) meaning (PE19/45). Both examples illustrate the sound change whereby pt becoming to ps. However, Tolkien abandoned this sound change and decided that pt became ꝑt [ɸt], though still spelt pt and later pronounced u̯t in Exhilic Quenya of the first age. As part of this conceptual change, Tolkien revised lapsa >> lapte with a new primitive form ✶labdē before deleting the entire section and rewriting it with new examples.
Neo-Quenya: I’d retain ᴺQ. laptë “gluttonous eating” for purposes of Neo-Quenya since the sound changes producing it remained valid.
licking up, gluttonous eating