Consider placing all tone marks at the first vowel following Yale convention

[AlienKevin]

For some vowels like iu, ui, eu, pingyambiu places the tone marks on the second letter. This may be a habit from hanyu pinyin where the tone marks are placed on the main vowels. However, the convention in Yale is to put the tone mark at the first vowel letter, not on the main vowel. This is evident in the textbook Speak Cantonese which first introduced the Yale romanization in 1960. I found a digitalized copy of the book and confirmed that indeed all tone marks are placed on the first vowel. Other dictionaries like CC-Canto also observe this convention.

biu and bui seen in the vocabulary section of the book (open digital version):

cheung and cheut seen in the vocabulary section of the book (open digital version):

Proposed updates

Here's a list of 127 Yale syllables I found in the pingyambiu that can be updated. If you find this useful, I can make a PR with these changes.

biū -> bīu
biú -> bíu
buī -> būi
cheūn -> chēun
cheún -> chéun
cheùhn -> chèuhn
cheūt -> chēut
chiū -> chīu
chiú -> chíu
chiùh -> chìuh
cheūk -> chēuk
cheūng -> chēung
cheúng -> chéung
cheùhng -> chèuhng
cheúhng -> chéuhng
deūn -> dēun
deún -> déun
dēeu -> dēu
deeuh -> deuh
diū -> dīu
diú -> díu
diùh -> dìuh
deūk -> dēuk
deūng -> dēung
ēeu -> ēu
fiū -> fīu
fiú -> fíu
fuī -> fūi
fuí -> fúi
giū -> gīu
giú -> gíu
geūng -> gēung
hiū -> hīu
hiú -> híu
hm¯ -> hm
hñg -> hng
heūng -> hēung
heúng -> héung
yeún -> yéun
yiū -> yīu
yiú -> yíu
yiùh -> yìuh
yiúh -> yíuh
yeūng -> yēung
yeúng -> yéung
yeùhng -> yèuhng
yeúhng -> yéuhng
kiū -> kīu
kiú -> kíu
kiùh -> kìuh
kiúh -> kíuh
keúng -> kéung
keùhng -> kèuhng
keúhng -> kéuhng
kuí -> kúi
leūn -> lēun
leún -> léun
leùhn -> lèuhn
leút -> léut
liū -> līu
liú -> líu
liùh -> lìuh
liúh -> líuh
leūk -> lēuk
leúk -> léuk
leūng -> lēung
leúng -> léung
leùhng -> lèuhng
leúhng -> léuhng
mēeu -> mēu
meeuh -> meuh
miū -> mīu
miú -> míu
miùh -> mìuh
miúh -> míuh
muī -> mūi
muí -> múi
muìh -> mùih
muíh -> múih
niū -> nīu
niú -> níu
niúh -> níuh
neúng -> néung
neùhng -> nèuhng
pēeu -> pēu
peeuh -> peuh
piū -> pīu
piùh -> pìuh
piúh -> píuh
puí -> púi
puìh -> pùih
puíh -> púih
seūn -> sēun
seún -> séun
seùhn -> sèuhn
seūt -> sēut
siū -> sīu
siú -> síu
seūng -> sēung
seúng -> séung
seùhng -> sèuhng
seúhng -> séuhng
teúhn -> téuhn
tiū -> tīu
tiú -> tíu
tiùh -> tìuh
tiúh -> tíuh
weūk -> wēuk
wuī -> wūi
wuí -> wúi
wuìh -> wùih
wuíh -> wúih
jeūn -> jēun
jeún -> jéun
jeūt -> jēut
jēeu -> jēu
jeeuh -> jeuh
jiū -> jīu
jiú -> jíu
jeúk -> jéuk
jeūng -> jēung
jeúng -> jéung
jeúhng -> jéuhng