Language /
Rok vs. Lat [30]
'Lata' is just plural of 'rok'.
Here are all the cases:
Singular:
M. rok
D. roku
C. rokowi
B. rok
N. rokiem
Mc. roku
W. roku!
Plural:
M. lata
D. lat
C. latom
B. lata
N. latami
Mc. latach
W. lata!
You just need to know the 1, 2-4, 5.. rule to use the proper case, and that's it.
And regarding the years-summers thing, it's common not only in Polish that names of seasons or other events used as measures of time (especially in older writings).
e.g.
moons-months (in (old) Polish Księżyc (moon) sometimes is called miesiąc (month)), Sundays-weeks (niedziele-tygodnie)
Springs-years (wiosny-lata (oh, this one really looks strange :-|) )
Some example, just a short love story ;-) (really old-fashioned)
Było jej sidemnaście wiosen. (she was 17)
Spotkali się w świetle miesiąca. (they met in moonlight)
W cztery niedziele byli już po słowie. (in 4 weeks the were already engaged)
If anyone still interested, in the past the plural of 'rok' used to be regular: roki
M. roki
D. roków
C. rokom
B. roki
N. rokami
Mc. rokach
W. roki!
but this form is not used any more in contemporary Polish (however, still perfectly understandable and correct from grammatical point of view).
Cinek