First things that comes to mind: Japanese for “to laugh” is 笑う “warau”. The equivalent of “lol” then started as 笑. Over time it evolved into just the first Latin letter “wwwww”. Which kind of looks like grass. And because Japanese people love word play, logically the next step was 草 “kusa” - which means “grass” and now also “lol”.

Anyway, sentences in languages that use logograms, such as Japanese, are generally shorter since they just use one character where languages that use Latin letters need several (“Want to hang out tonight after school?” - 授業後今晩遊ぼう？). So standard text message character limits are plenty to convey A LOT of stuff in Japanese.

You can make sentences more compact if you want to: 今晩　遊？ is not a complete sentence but the essential parts that carry the meaning, “this evening” and “hang out”, are there so if you’re in a hurry that’ll do.

Going further back in time might be more interesting, the Japanese did some crazy shit with pagers: japanesewithanime.com/…/spelling-words-using-numb…