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.
SMS message length can be severely restricted when using special characters that are outside this character set.
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.
Avoid using special characters
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.
iPhone issues with special characters
iPhones use a special character by default for the apostrophe (for example in auto-correct). When typing and it auto-replaces 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.
