in German it's even more obvious:
"fangen" vs "Gefangnis"; the second means "caughtness" literally (caught = gefangen)
It appears they are, but I don't think -nga is a suffix, but rather that there are two verbs that've developet into different meanings from a common root.
It sounds more natural to say 'the dog tries to get the cat' , but it isnt accepted
is there something like a general rule when att is needed and when it isn't?