Year 4 music: Why d-r-m-f-s-l-t-d'?

I designed 2 questions into my Year 4 classroom these two days so as to facilitate discussion around the topic of music notations; and they are:

1) We've always relied on a sol-fa system to learn music - but why do-re-mi-fa-so-la-ti-do' not any other strings of non-sense syllables? In other words, where does this system originate?

2) The sol-fa system, by its alphabetical appearance, is cultured as only people who know alphabets can read. It can be argued that it's not a universal system. Can you, children, come up with a notation system that is can be used universally, freed from cultural boundaries?

It was a delightful discussion. Certainly, no one would know the origin of the sol-fa system unless you deliberately research for it (like I had to do for this lesson); the reasons generated through the discussion were quite creative:

1) The creator of music had 8 sons, and they were named Do Re Mi Fa So La Ti Do' respectively.

2) The creator of music decided to do a lucky draw and set each pitch to a syllables; and the winners are Do Re Mi Fa So La Ti Do'

3) Beethoven invented it

4) Once a upon a time, there is a village full of witches. When the withces perform witchcraft, they sing a strange spell; this has become a tradition. Many years later, tourists start visiting the village and heard this string of syllables and thought it sound good; so they decided to share it with the rest of the world.

5) It came from a mysterious murder. 8 presidents were killed and there was blood stain on their bodies. The blood stain reads Do Re Mi Fa So La Ti Do'.

This may give you some hint...