I find it depends on the surrounding words as to how some words are pronounced, e.g. fire, Ireland, frail (as you say). Diphthongs get a bit tricky, and of course accent mucks things about too. I write the way I say things but do try to not confuse people too much (for example, it really seems to upset Americans when I use the word "arse" because they think it doesn't rhyme with "grass" that way. It totally does when I say it. And my husband is Scottish, so for him it's perfectly acceptable to rhyme "girl" and "squirrel". Language is weird.)
It could be worse