It just occurred to me that writing reäl with a diæresis is useful for indicating the pronunciation /rɪəl/ rather than /ri(ə)l/ (or /riːl/?). Are there any occurrences of this in literature? (Is there a freely available corpus of English lit. that will settle this?)
There seems to be at least one text where a dieresis occurs over the "e" in "real", but I think that in practice, this is no longer an option in normal English writing.
From Google Books:
And they have indeed a great influënce, when preſented in his Spirit, as aforeſaid, to work in our hearts true and reäl repentance from all our ſins