I would really appreciate to see what is the rule for M or N in sufixes. e.g. here... alguMas x alguNs
When the word finishes in "m" the plural is made by changing "m" for "ns" . Alguma ends in A, so just add S (algum - alguNS, alguma - algumaS, ruim - ruiNS, amendoim ' amendoiNS) there is no portuguese word ended in N (except for foreign words...)