French extra characters to be added to its alphabet of 26 letters for
spelling purposes:

                        Accents affecting letters
Letter          ACUTE   GRAVE   CIRCUMFLEX      DIAERESIS       CEDILLA

a                       x       x
A                       x       x
c                                                               x
C                                                               x
e               x       x       x               x
E               x       x       x               x
i                               x               x
I                               x               x
o                               x               *
O                               x               *
u                       x       x               x
U                       x       x               x
y                                               x
Y                                               x

The * above is an innovation: it is not a traditional French letter but I
have to conclude it is now French, given the rationale above. Y DIAERESIS
was in the same situation in the XIXth Century and became a full-fledged
French letter later on.

Ligatures (joined digraphs if you wish):

ae, AE, oe, OE