a: Pronounced as "ah", similar to the sound of "a" in "father".
e: Pronounced as "eh", similar to the sound of "e" in "set".
i: Pronounced as "ee", similar to the sound of "i" in "sit".
o: Pronounced as "oh", similar to the sound of "o" in "hot".
u: Pronounced as "oo", similar to the sound of "u" in "put".
In terms of consonants, Tongan also uses the following:
b: Pronounced as "b".
c: Pronounced as "th", similar to the sound of "th" in "thick".
d: Pronounced as "d".
f: Pronounced as "f".
g: Pronounced as "ng", as in "sing".
h: Pronounced as "h".
j: Pronounced as "ch".
k: Pronounced as "k".
l: Pronounced as "l".
m: Pronounced as "m".
n: Pronounced as "n".
p: Pronounced as "p".
q: Pronounced as "ng", as in "sing".
r: Pronounced as "l".
s: Pronounced as "s".
t: Pronounced as "t".
v: Pronounced as "v".
w: Pronounced as "w".
y: Pronounced as "y", similar to the sound of "y" in "yes".
Keep in mind that these are general pronunciations and may vary slightly depending on regional accents within Tonga.