I've switched the noun and adverb/case tag endings. Since nouns ended in "s" and were followed by words beginning with "z" (conjunctions and numbers and "zo-" words), it was hard to keep the "s" from merging with the "z".
Nouns now end in "t" (closed) and "d" (open), and adverbs in "s" and case tags in "z".
I expect this change to make it easier to keep the words from merging.
Separating adverbs and case tags may be new here, but it's been in the air a long time.
stevo