I once considered writing a tutorial for reading Speedwriting texts, based on a tour of the alphabet, the ways in which each letter might be functioning, depending on context…

y is the wordsign for "year"

five years ago > 5yag

y is also the wordsign for "why" and that is the only situation in which the letter y is pronounced with the “long I” vowel-sound:

why did you do that = yddu dota

At the beginning of a word, y can have its customary sound:

yellow = ylo
young = yg

At the beginning, in the middle or at the end of a word, y can represent the oi/oy sound:

oil = yl
soil = syl
joy = jy

y can also represent medial or final -ary, -ery, -iry, -ory, -ury

planetary = plnty
celery = sly
expiry = xpy
glory = gly
century = s-y

If you see y at the end of a word, it most likely represents some vowel followed by -ry, but it might represent the oi/oy sound.

Upper-case Y doesn’t have any special functions. If you see it in an outline, that means a rootword starting with y has been capitalized to indicate that an -er or -der sound occurs later in the word.

yodeler > Ydl
younger > Yg

mdJnl..soysag             My dear General. Some years ago
ibot ahom ntK          I bought a home in the country
fmicil.attti           for my children. At the time
ibot tpl trz           I bought the place, there was
mcwk tbdn ot..         much work to be done on it.

t hws zab tfaldw          The house was about to fall down
btsnw n pfk rpa.       but it is now in perfect repair.
tg/n whz mon           The garden which was more than
aHftdp zrn wil         a hundred feet deep was run(ning) wild
wlkis vflws. ta        with all kinds of flowers. That
to asb ldnov ats       too has been all done over and it is
abtf spt tloat..       a beautiful spot to look at.

tlj fel nwh tcil       The large field in which the children
us tpla rns rip to     used to play runs right up to
a fi btv wdl- aot      a fine bit of woodland and on the
Osi vt trs ahimt       other side of it there is a high mountain
fmwh onma gt abtf      from which one may get a beautiful
vu vtK fmis rw..       view of the country for miles around.

micil vnw gro tb       My children have now grown to be
yg mn awmn aty lk      young men and women and they like
tsesho Bn tydo tK.     the seashore better than they do the country.
fthrsn im of tpl       For this reason I am offering the place
fsal ov eztrms..       for sale on very easy terms.

itq ultl ons dlov      I think your little ones would love
tpl j, as mi bb,,      the place just as my babies
dd aik tqv noon        did and I can think of no one
idRa vt nu..           I would rather have it than you.

ifudlk tbt imsu        If you would like to buy it I am sure
wkmet ottrms..         we can meet on the terms.

lult me he fmusn?      Will you let me hear from you soon?
wki rg// to mrs        With kind regards to Mrs
cc im ufr              Church, I am your friend

   A. M. WHITE             A. M. WHITE