[3] In the phonology of Standard French, the letters ie are normally pronounced [je] or [jɛ] except after Cr or Cl, when they indicate two syllables, [ije] or [ijɛ].
In Standard French, the pronunciation of hier (yesterday) varies between the two, [jɛʁ] or [ijɛʁ], depending on the context.
Diaeresis as separate pronunciation of vowels in a diphthong was first named where it occurred in the poetry of Homer.
If the pairs of vowels are contracted into diphthongs by synaeresis (i.e., Ὀδυσῇ δαίφρονι) and the diphthongs are placed in one syllable each, one foot (in red) no longer follows the patterns, no matter how the line is scanned: In Homer, compounds beginning with ἐύ- (also spelled ἐΰ-, with a diaeresis or trema) frequently contain two separate vowels (diaeresis).
The word comes from εὖ "well",[4] the adverbial use of the neuter accusative singular of the adjective ἐύς "good".