SMS and Text Encoding

SMS messages use a special and limited character set.

SMS messages use a character set called GSM-7 encoding by default, which supports 160 characters per message. Any character outside the predefined GSM-7 character set (such as certain symbols, emojis, or special punctuation), switches the message to use UTF-16 (UCS-2) encoding, which reduces the character limit to 70 characters per message.

Restricting character usage to a regular apostrophe, a dash instead of a long dash, or three periods instead of an ellipsis is a way to work around this limited character set.

If you’re copying/pasting your message from another program like Word, they will often times carry over these special characters, for example.

iPhones use a special character by default for the apostrophe (for example in auto-correct). When typing and it auto-adds it, you can delete it, then press the "123" button to see special characters: tap and hold on the apostrophe and you will see other options, including one that looks more like a straight line for an apostrophe. This is the "regular" apostrophe.