In Illunse, pronounce i as in police and machine. Make the sound short, similar to y in very or like how i is pronounced in Spanish. This is how short i, or i without an accent is pronounced in Old English.
In Illunse, pronounce ie as i in pit or his. This is as short i is pronounced in Latin. In Old English ie and íe are instead diphthongs.
In Illunse, pronounce ea as in bead and eat. Make the sound long. This is as í, long i, accented i, is pronounced in Old English. This is how ī (i macron) or long i is pronounced in Latin. In Old English ea and éa are instead diphthongs.
I may need to modify some existing words for pronunciation.