The Disappearing "That"

In English, the “that” is often implied as in:
I hope (that) you will come tomorrow.
I’m no linguist but I remember from school French and Spanish that, in those languages, you couldn’t omit the “that” but had to say it.

However, in SSiW, they do seem to omit the that/bod from the Welsh quite often so:
I hope you will come tomorrow = dw i’n gobeithio _____ ddoi di yma yfory.

Is Welsh like English inasmuch as “that” is optional or do I need to go Googling Welsh grammar to see what rules are operating here?

The following thread may (or may not! :grinning: ) be of use to you if you read the whole thing. (It’s not too long!)