However, it's not as widely used as abbreviations for other words, and it might not be clear to everyone what it stands for. It's generally best to use the full word unless you're writing in a very informal context.
Here are some other possible abbreviations, though they're less common:
* spk
* sp
* spking
If you're unsure about the best abbreviation to use, it's always best to check with your audience or use the full word.