I am making a conlang called Keplerian Proto-Arab. Keplerian is because it is on a planet with Kepler in its name. Proto is because this is the first language of a language family. And Arab is because it is based off of Arabic but is not itself Arabic.
So the first step is the phonemic inventory and I already have the Arabic phonology for consonants in my phonemic inventory. Namely:
m
n
p
b
t
tˤ
d
k
kˤ
q
ʔ
f
v
θ
ð
s
sˤ
z
zˤ
ʃ
x
ɣ
χ
ʁ
ħ
ʕ
h
d͡ʒ
l
ɫ
j
ɰ
r
But should I add other consonants to it and what vowels should I add to it?
I do want the writing system to be either an alphabet or an abugida, I don't know which.