Etymology

Thai keyboard

Pressing the letter ถ ‎(tɔ̌ɔ) on a Thai keyboard after switching the language from Thai to English results in "5". In Thai, "5" is pronounced "ha". Thus, "555 ‎(555)" is "hahaha". "ถถถ" is the result of (sometimes purposely) failing to switch the language when typing "555 ‎(555)".

Pronunciation