diacritic position of comma accent..

Mithil Mogare

I encountered with some comma accent position variation in some letters like ģ, ķ, ļ, ņ, ŗ in one blog.
Does comma accent similar to cedilla?
Will the position of comma accent be on the top in letter g, like this ģ? 
In which languages do we use comma accents?

Olexa Volochay

Plz, read this article http://diacritics.typo.cz/index.php?id=9