We are going to have a look at the Gaelic sound made by the letters ch.
When it is used before or after the broad vowels (a, o or u), ch has a harsher sound most easily recognisable in words like cha, which we use to say that something is not the case.
You can also hear this ch sound in loch:
a loch (or lake)
The Loch Ness Monster
When used before or after the slender vowels (e or i), the ch sound is much lighter, and can be heard at the end of duilich, which is the Gaelic for sorry:
Or at the beginning of chì, which means to see: