Some letters look different when they appear at the end of a word.
Greek:
Only the sigma has a final form. It looks like σ in the middle of a word and ς at the end of a word.
Hebrew:
The following letters have final forms; see page 3 here or this video
A כ looks like ך when it is the last letter of a word.
A מ looks like ם when it is the last letter of a word.
A נ looks like ן when it is the last letter of a word.
A פ looks like ף when it is the last letter of a word.
A צ looks like ץ when it is the last letter of a word.
Eichorn asks whether these letters might have been used to separate words. source