From That Spelling Thing - 3rd Edition of the book is now on Amazon in your country.

Whenever I get talking to a teacher about spelling, I offer them my brilliant idea that every school should, in the first couple of weeks of the first term, have a '-tion Day' when each first-year student and teacher will adopt a useful word ending in -tion. By the end of the day they will know what it means, how to say it naturally, say it for spelling, and, of course, spell it accurately.

I used to end that conversation by saying something like, 'I know there are other ways to spell the /shun/ (or /zhun/) ending, but <tion> is by far the most common.' I'd been making that assertion based on experience rather than research so thought I'd dig a little deeper to back up my claims.

If you like finding word patterns, then you probably know thefreedictionary.com. I usually get there by searching for something like 'words ending in' or 'words starting'. This time I got a huge list and scooped off just over 700 words I thought would be the most common, put them in alphabetical order and sorted them by <tion>, <cian>, <ssion>, <cion> and <sion>.

As always, memory is required for spelling but we can also play the odds a little.

<tion>

According to my list, 83% of the time, when you hear /shun/ or /zhun/, the spelling is <tion>. On that basis, you don't really have to do much sorting and looking for patterns unless you really want to and your students find it helpful.

• A trustworthy pattern is, if you hear /ayshun/ then write <ation>. I've never met an exception.
•  Roots that end <t> ten to have the <tion> spelling: attract/attraction etc fit the pattern but lots of roots that don't end in <t> also add <tion>.
• A more advanced pattern: absorb/absorption - subscribe/subscription - describe/description - all reflect a shift in pronunciation from /b/ to /p/.
• Your more confident spellers might enjoy going deeper through word study or by looking at phonetics and pronunciation. For unconfident spellers, that kind of study is likely to be a barrier to learning.

Instead of trying to sort the 83% spelt <tion>, let's look at the remaining 17% - around 120 words with their various spelling options. I've left some words with 'no obvious (to me) pattern'. A pdf of the full list is linked at the bottom of the page.

<cian>

• These words are jobs music/musician, optic/optician - even more fun if you're working with someone called Ian.

<ssion>

• These words largely have roots that end <ss> impress/impression and a few that end <mit> admit/admission.

<cion>

• There are only two common words with this spelling: suspicion and coercion. So learn those two words and exclude <cion> from the list of options.

<sion>

This is where you might have to use more memory but there are some good patterns.

• Listening for /zhun/ rather than /shun/ helps.
• If the verb is spelt with a split digraph plus <d> then it's <sion>. Lots are accounted for with this pattern. collide/collision, deride/derision
• If the word ends in <d> by itself, the ending will sound like /shun/. apprehend/apprehension, extend/extension.
• Roots ending <vert> invert/inversion. It might be easier just to hang all those words on one familiar one: version.
• Likewise, any word ending <vision>: revision, television
• A handful of roots ending with /r/ or /l/ with no vowel added. adhere/adhesion (as opposed to adore/adoration), compel/compulsion
• Roots ending with the sounds /s/ or /z/ when no vowel is added. precise/precision, transfuse/transfusion.
• 'No vowel added' means we have confuse/confusion (no vowel added) but accuse/accusation (vowel added).