Normally when a vowel or vowel combination is followed by the
letters m or n, that vowel is nasalized. When this is the case
the letters m or n are not pronounced; they serve only to mark
the nasalization.
un bon vin blanc
a good white wine
The letter combinations ain, aim, eim, ein, in, im, ym, yn and ien
all have the nasalized vowel sound [].
faim
train
bain
pain
main
sainte
plainte
plein
enceinte
sain
vin
pin
prince
singe
syndicat
simple
sympathique
thym
moins
poing
nasalized []
oral
certain
chien
le tien
il vient
cousin
certaine
chienne
la tienne
ils viennent
cousine
The letter combination un is pronounced with the nasalized vowel [].
brun
parfum
Verdun
lundi
commun
nasalized
oral
un
aucun
une
aucune
The letters an, en, and em are pronounced with the nasalized
vowel []
dans
Jean
dent
vent
emporter
emmener
etudiante
enfant
danse
ils vendent
ils mentent
elles chantent
constante
intelligente
lente
pendant
ingrédient
vient
viens
client
The letters onare pronounced with the nasalized vowel []
mon
pont
bon
station
honte
monde
nasalized
oral
son
Simon
sonne
Simone
The letters n or m following a vowel combination don't always
signify a nasal sound. When the n or m that follows the vowel
is the last letter in a word or if only a single consonant follows the m
or n, the vowel is always nasalized.
banc
champ
quand
temps
teint
plomb
sens
But if the m or n is followed by a mute e the vowel is not nasalized.
The third person verb endings (-ent) are considered a mute e.
ils dînent
fine
If a vowel immediately follows the m or n and that vowel is not
a mute e, the m or n is part of the syllable of this vowel
and is therefore not nasal.
].
]
.
] 
]