A word in The Etymologies of the 1930s glossed “line, row”, derived from primitive ᴹ✶tēñe under root TEÑ (Ety/TEƷ). It might replace N. tê “line, way” < ᴹ✶teʒē based on the earlier form of the root ᴹ√TEƷ (Ety/TEƷ), or the two words might co-exist: with tî the result of long ē becoming ī [✱tēñ(e) > tī(ʒ)] and tê retaining e because the e was not long primitively [✱teñē > teʒe > tē].
Conceptual Development: ᴱN. tî or tí “line” appeared in the Early Noldorin Grammar and Early Noldorin word-lists of the 1920s (PE13/121, 154). The Gnomish Lexicon of the 1910s had G. tî as an adjective meaning “straight” but also a noun meaning the same thing as either G. tion “a straight line” or G. tê “mark, line; track; path” (GL/69, 71).
Neo-Sindarin: For purposes of Neo-Sindarin, I would assume tê and tî coexist, with tê “line, way” used for a continuous line, but tî for a line or row of discrete items, as in [N.] tiwdi “alphabet, (lit.) ✱letter-row”. I would further assume they were based on the later root √TEG “line” (PE19/97), from primitive ✱tegē and ✱tēge respectively.
A word in The Etymologies of the 1930s glossed “line, way”, derived from primitive ᴹ✶teʒē under the root {ᴹ√TEƷ >>} TEÑ “line, direction” (Ety/TEƷ). Given the change in the root, the primitive form may have become ✱teñē as this would have produced the same result. Alternately, this word may been revised to N. tî “line, row”; see that entry for discussion.
Conceptual Development: In the Gnomish Lexicon of the 1910s, G. tion meant “a straight line” (GL/71) while G. tê or tî meant “mark, line; track; path” (GL/69). The 1910s form tê was derived from ᴱ✶teʒ́e but tî was derived from ᴱ✶tē because long ē became ī. Compare later N. tê < ᴹ✶teʒē vs. N. tî < ᴹ✶tēñe; see the entry for N. tî for discussion.