-ez (Breton) comes from Proto-Brythonic *-es, from Latin -issa, from Ancient Greek -ῐσσᾰ, from Ancient Greek -ῐ́ᾱ, from Proto-Indo-European -íh₂, from Proto-Indo-European -h₂ — Creates collective nouns, which refer to groups...
-ez (Breton): -ess