Translation:Türkçe ve İngilizce biliyorum.
What's the difference between using 'c' with a cedilla or 'c' without for the different languages' endings?
C follows a vowel or a soft sound like m n l z r
Ç follows a harder or aspirated sounds like k p ş ç t
Somewhere there is the entire list of letters, but for now hopefully this gives you an idea.
Two different sounds. "c" is a voiced sound like the "j" in jury or jacket. "ç" is LIKE that sound in terms of what your mouth is doing but voiceless, without your vocal cords moving -- it sounds like "ch" as in church or child.
So, -CA is an adverb suffix that means "in this way." It's used to form languages from ethnicities (and other things). (Türk + -CA=Türk-çe)
The C becomes "ç" if there is a voiceless consonant before it (ç/f/h/k/p/s/ş/t). The C becomes "c" if there is a voiced consonant or a vowel before it (b/c/d/g/j/l/m/n/r/v/y/z/aeiıoöuü).
The A follows vowel harmony, so it the previous vowel is a back vowel (aıou) it's "a", if it is a front vowel (eiöü) it is "e."
Türk-->Türkçe (k is voiceless, e is front=-çe) suffix sounds like "che" of English "check"
Arap-->Arapça (p is voiceless, a is back=-ça) suffix sounds like "cha" of English "chalk"
İngiliz-->İngilizce (z is voiced, i is front=-ce) suffix sounds like English "jay" (but shorter)
Japon-->Japonca (n is voiced, o is back=-ca) suffix sounds like English "jaw" (but shorter)