Why are my messages with unicode being split?
When using the deprecated SMS/Messages resource URI to send text messages, messages with one or more non-GSM characters are limited to 70 characters. Any SMS messages that include 1 or more non-GSM characters will be separated by Twilio into messages of 70 characters or less. You can find out what characters are included in the GSM set here. You can also paste the text you’re attempting to send on a third-party checker to verify your messages are free of non-GSM characters. Here is an example link that works as of fall 2015.
If you are sending unicode messages to mobile numbers in US and Canada, try the Messages Resource URI instead. You can send messages containing up to 1,600 characters without being split. Check out this FAQ to learn more.
NOTE: Regardless of the resource you are using, text message are billed in 160 character increments for GSM characters and 70 character increments for non-GSM characters. For more information on how this works in REST API, please see the Num Segment documentation.