There must have been a way to decipher the language, to some extent at least, since so much is already known about their culture.
Since this is a discussion on time, people can use other methods, like those of the Aztecs who did indeed have pious dates carved into their calender, still made it effecient enough without a connection to religion/god. Sundials would work too, it'd get complicated trying to keep track of the years though....
Not to mention science which deals with seasons, just keep track of the equinoxes throughout the year. Or you could follow the waning and waxing of the moon....
Since this is a discussion on time, people can use other methods, like those of the Aztecs who did indeed have pious dates carved into their calender, still made it effecient enough without a connection to religion/god. Sundials would work too, it'd get complicated trying to keep track of the years though....
Not to mention science which deals with seasons, just keep track of the equinoxes throughout the year. Or you could follow the waning and waxing of the moon....