If you’re not asking about anything that we currently don’t have a word for, we can use words as the alphabet, sure.

We then need to transmit a list of words, they’re allowed to use, otherwise our count is off, because I’m sure that 974 years from now english won’t be the same, as it is today. They’ll have a lot more skibid rizz than we do now.

busted

Once you’re able to use time as an information, they can send a message with a character limit. For every letter they need to wait:

Remaining Message Length^Alphabet Size*Index of Letter*time interval

So, if future people want to sent the message hello and our time unit is 1s, and the max message length is 5, they need to send the bit to exactly 26^4*7+26^3*4+26^2*11+26^1*11+26^0*14 = 3276872 seconds or 54614,5333min or 910,242222h or ~38 days after the start time.

We can choose smaller time intervals, but with a long enough message, we’ll eventually reach the year 3000 again. Alternatively, we can move the start time into the past, at the expense of quite a few possible messages.

This is the same problem as trying to map an n-dimensional array to a one dimensional array

Hmm, maybe try east greenlandic?