A rejected adverb in the Gnomish Lexicon of the 1910s glossed “wherewith, far, long, away”, with the first gloss “wherewith” being unclear (GL/53). It was like derived from the early root ᴱ√LENE (QL/53), which was apparently revised to ᴱ√leŋe (GL/53).
Gnomish
len
adjective. come, arrived
len
adverb. wherewith, far, long, away
glen(n)
adjective. thin, fine, slender
nôbi i·mab ’len suila ontha
*he took the slender hand of his daughter
im len
I have come or am come
An adjective appearing as G. len “come, arrived” in the Gnomish Lexicon of the 1910s (GL/53), likely based on the early root ᴱ√LEHE “come, be sent, approach” (QL/52). Tolkien said it was “used also with the forms im, on [emphatic pronouns], etc., as a perfect. ‘I have or am come’ as im len, um lenin, etc.”.
Neo-Sindarin: For purposes of Neo-Sindarin, I would instead use the perfective active participle ᴺS. túliel “having come, having arrived”.