We knew that land once, You and I,
and once we wandered there
in the long days now long gone by,
a dark child and a fair.
Was it on the paths of firelight thought
in winter cold and white,
or in the blue-spun twilit hours
of little early tucked-up beds
in drowsy summer night,
that you and I in Sleep went down
to meet each other there,
your dark hair on your white nightgown
and mine was tangled fair?
- J. R. R. Tolkien, The Little House of Lost Play: Mar Vanwa Tyalieva
The word separators were the biggest clue. I began by highlighting all of the repeated words. The separators also told me the very first word could not be a one-letter word, or else there are too many unique one-letter words (and I'm already expecting one extra for
the). This tells me the horizontal line is a separate letter. There aren't many two-letter words I expect to find at the beginning of a sentence, mostly
WE. The most frequent three-letter word is either
AND. After assuming
AND, the second repetition of
WE was right next to a long word beginning with
W and containing a few of
NDE. A pattern search turned up the word
WANDERED, which confirmed that the horizontal stroke across the letter meant a letter
E followed that letter, and likewise the curve below means
A. Then, a word following
WE and ending in
W has to be
KNEW. I continued solving it as a simple substitution and learned that the vowels have whole-symbol forms (in addition to the combining forms) for when they appear at the beginning of a word, and in other places.
By the time I completed the line
in the long days now long gone by, I decided to google it and found the source. So I only discovered the "double letter" combining symbol after the fact.
The only tools I used were the drawing program Inkscape, and a small program I wrote for finding dictionary words according to various patterns.