Filrul is hard to pronounce!
We could go for something really out there like -oq or -okt. Maybe even two syllables like -oktah but that would be very long.
Some more 'out there' suggestions beggining with vowels...
-ad -ahp -ekt -ul -uv -upt -opt -est -ehr -uft
-uf -ahz -avaz -uzr -aq -asp
Then we'd have to decide on a consenant to use at the start should a word end in a vowel. This is some real tough cheese here.