The 'shun' sound can be spelt in three different ways. Which one you use depends on the last letter or letters of the root word.
- If the root word ends with 'c' or 'cs' use the -cian suffix: magic - magician
- When the root word ends with 'd' or 'se' the suffix used is usually -sion: expand - expansion
- If the root word ends with 't' or 'te' use -tion: invent - invention
Can you think of any more?