Aaaand some months later when I've got bored enough to put actual effort into solving it: got sensible English out of most of it, but shifting the Polish three letters in either direction only gets me gibberish, and even if I could figure out which way actually makes sensible Polish words (betting it's the way that the last five letters are 'JAWAS', but don't know), I don't have the faintest idea where the word breaks are. And even if I did know what the Polish words were, it's Babelfish. (Or Poltran, but same principle.) The preceding sentences, Poltraned English to Polish to English, come out as follows:

understands some later (late) months * * ( ) Aaaand poźniej when I has receive ( received; sufficient has gotten ) * * sufficient amount ( bored; attempt (test) litters sufficiently ) test (try) (; don't beguile it try ) solve received sensible english out of most of it, but letter removing ( changing ) polish three letter (list) ( ) in (to) either (or) each direction ( ) management ( ) only receive ( obtain (get); it understands me litters ) &, and even if could calculate which way sensible polish produce actually ( polish < poland >; it formulates brilliance be set-up center (means) ) word ( ) ( setting up (bet; found) ( ) expensive (dear) < way > ( ) that (in order to) last five letters (lists) are ( letter ) ' * ' * JAWAS, but it does not learn ), it don't beguile faintest (faintest) idea where breaks of words are. And even if I make learn that polish ( polish < poland >; was brilliance ) word, there is < > * * Babelfish. ( Either (or) * * Poltran, but same base. )

What was it before Cam put it through Poltran?