swans
more than one lynx is call lynxes
you call them possums if your talking about more than 1
More than one fisherman is fishermen
More than one platypus is two or more platypuses. The plural is not 'platypi'.
Fish
Ants
Pegasi I think.
Vampiresses.
Polygamy.
its just fishermen
two goats
A person who speaks more than one language is called a polyglot.