A demonstrative appearing in Demonstrative, Relative, and Correlative Stems (DRC) from 1948 associated with the familiar 2nd person ᴹQ. ke “you” (PE23/96, 98-99), hence used to refer to the place of the person being addressed = “✱that by you”.
Neo-Quenya: In earlier pronominal charts from this period, ᴹQ. ti was initially used for 3rd person pl. “they”, but in later writings this became te. Meanwhile, the familiar “you” later became tye derived from ✶ki. Thus I think ti remains plausible as an (obscure) second person demonstrative “that by you”, but I would use it sparingly compared to the more ordinary ta “that”.
Conceptual Development: The Qenya Lexicon of the 1910s had ᴱQ. ena “that by you” derived from the early root ᴱ√E of similar meaning (QL/34).
A noun in The Etymologies of the 1930s glossed “a glint” derived from the root ᴹ√TIN “sparkle, emit slender (silver pale) beams” (Ety/TIN).