"I have an orange cat."
Translation:Mae gen i gath oren.
This is an example of 'soft mutation', something very common in the Celtic languages.
The root word is cath (a cat):
- Mae cath oren gen i.
- Mae cath oren gyda fi. No mutation
If we move the gen i, say, to a different position in the sentence, as is quite common in Welsh, this triggers a soft mutation of c- to g- in the immediately following word, (as explained in the notes to the section 'May I?' earlier in the course):
- Mae gen i gath oren.
There are many causes of soft mutation (35-40, perhaps), and the best way to learn them is as you come across them one by one, as happens in this course. This course only introduces the main causes, though, so don't think you will face an avalanche of them!
Don't worry about missing a mutation, though, as you will be understood well enough without them. Some of them seem to be slowly dying out through lack of use anyway, as the language continues to change over time.