Sugar and sure begin with the letter S but start with a SH sound, because the pronunciation changed in the Middle Ages and the spelling stayed behind.
First, how do you say them?
sugar: SHUG-er
sure: SHOOR (or SHOR)
The first sound is sh, like in ship. There is no “s” sound at the start of either word.
The weird part
In most words, s says s: sun, sit, sand, soup. Here, the same letter says sh.
spelling: sugar, sure
sound: shugar, shoor
Learners who meet these words in writing first often say SOO-gar by mistake.
What changed
Long ago, these words began with a plain s sound, followed by a yoo sound, which is how the word you begins. Say s-yoo-gar slowly and you can feel the mouth run from s straight into y.
The change happened sometime during the Middle English period. The mouth took a shortcut: the s and the y squashed into one sh sound. This is easier to say than keeping two sounds apart.
By then, the spelling was already fixed in writing. So the pronunciation moved and the spelling stayed.
It also happened in the middle of words
The same shortcut changed other words. In pressure and nation the sound is in the middle, and it is also sh. That is why nation is NAY-shun and not “nay-tee-on”.
For a fun example, see the made-up word ghoti, which uses the ti in nation to say sh.
🗣️ Natural Examples
I put one spoon of sugar in my tea.
Are you sure it is today?
Sure! I can help.
Too much sugar makes the cake very sweet.
I'm not sure where I left my shoe.
⚠️ Common Mistakes
Do not start with an s sound.
❌ SOO-gar
✅ SHUG-er
Sure and shore sound close.
❌ I am shore it is time.
✅ I am sure it is time.
Not every su- word does this.
❌ SHUN for sun
✅ sun, sum, sup and super keep the s sound.
💬 In a Conversation
Sam: Is there sugar in this juice?
Mia: Yes. Are you sure?
Sam: I am sure that I saw it.
Mia: Then say it properly: SHUG-er.
Sam: I did. The cat is the one who said SOO-gar.
⏳ The OddLingo Timeline
Earlier English: s + yoo (a plain s, then a y sound)
↓ the two sounds squash together
↓ s + y becomes sh
↓ the spelling stays with s
↓ today: sugar = SHUG-er, sure = SHOOR
🥡 The OddLingo Takeaway
When su- comes at the start of sugar or sure, the S says sh. It is not a rule you can use for every word, so learn these two as small exceptions.