'i' pronouncing - spirit x spine

[Abstract Idea]

I would like to know if there is any rule regarding the pronouncing of the 'i' in English words. I mean on words like:
spin x spine
spirit
direct x ditransitive
Italy x Ireland
Chile x China
In the list above I guess on the words on the left the 'i' sounds as 'ee' and
on the right it sounds as 'ai'. Two questions:
1) Is there any rule at all to know the right pronunciation ?
2) Do native English speakers sometimes have doubts regarding such pronunciations? For example if a native English speaker does not know the word 'spinor' would he have any doubt on its pronunciation ?

[konungursvia]

All those words are heavily influenced by their original pronunciations in other languages: French, Latin, Italian, Irish, Spanish... We do sometimes have doubts, and no there is unfortunately no simple rule that will simplify it a great deal.

[Abstract Idea]

Thank you very much konungursvia. Actually that is what I suspected, but I really needed to confirm from a native speaker.