The case with "hoppas" is a little bit special. By just having the fragment of the statement it is hard to tell what your friend referred to but I guess it could be expressions like the following "I hope I will pass the exam". In that case it is common to leave out the first I and infinitive "att" so that instead of "Jag hoppas att jag klarar tentan" you just say "Hoppas jag klarar tentan".
simmer isn't a word in Standard Swedish, although there are some dialects (Värmland comes to mind) that will consistently pronounce the -ar at the end of any verb as -er.
There's variation for the past tense though: today most people say simma, simmade, simmat 'swim, swam, swum' but in the past, simma, sam, summit was more common.