From what your that seems a 'feature' (some people would call it a 'bug', only the author can tell the difference) specifically for that iriver (or maybe all irivers), not generally for all shuffle programs on all mp3-players? Did you try the iPod shuffle already (it's a pity it's only 2GB, that's some 2000 tracks)?
when i choose to play the songs from "all songs" on shuffle mode, if i am choosing a song in English from the list the shuffle would not change to a song in Hebrew(my native language) at all, no matter how many songs will be afterwards.
so i thought it was statistics because i have more songs in English than in Hebrew.
but when i am choosing a song in Hebrew the shuffle would not "choose" a song in English at all even though i have more songs in English
i am trying to find out if there is a way i can enjoy music both in English and in Hebrew on shuffle mode(sometimes a songs in English and sometimes songs in Hebrew,randomly)