Case conversion for monotonic Greek

The basic rules for case conversion of monotonic Greek are simple:

1. all accented letters lose the tonos; and
2. all instances of the dieresis remain.

Difficulties arise with round-trip conversion (reversing to lower-case), capital-to-lower-case conversion, the handling of proper names with accented initial letters, and diphthongs or double vowels. We will look at each case below.

According to the first rule, the conversions are:

ά > Α,  έ > Ε,  ή > Η,  ί > Ι,  ύ > Υ,  ό > Ο,  ώ > Ω

(When α ε ο are not parts of a dipthong with ι! See below for these cases.)

Here are some examples:

πάμε τώρα >  ΠΑΜΕ ΤΩΡΑ

έλα πίσω > ΕΛΑ ΠΙΣΩ

φύγε μόνο εσύ
 > ΦΥΓΕ ΜΟΝΟ ΕΣΥ

According to the second rule, the conversions will be:

ϊ > Ϊ,  ϋ > Ϋ,  ΐ > Ϊ,  ΰ > Ϋ

Here are some examples:

φάγαμε καϊμάκι > ΦΑΓΑΜΕ ΚΑΪΜΑΚΙ

φύσηξε ο μαΐστρος > ΦΥΣΗΞΕ Ο ΜΑΪΣΤΡΟΣ

έχει αϋπνία > ΕΧΕΙ ΑΫΠΝΙΑ

επιτυχής εξαΰλωση >
 ΕΠΙΤΥΧΗΣ ΕΞΑΫΛΩΣΗ

Note that both ϊ and ΐ convert to Ϊ. Similarly, both ϋ and ΰ convert to Ϋ. This means that, unless you have access to a dictionary, you do not know if a capital Ϊ or Ϋ should convert to a lowercase ϊ or ΐ (and ϋ or ΰ respectively). The problem is solved if the capital forms arise from conversion of a correctly keyed in lowercase ΐ or ΰ, but not if the capitals have been keyed in directly: in those cases, it is highly likely that the user typed the standard keystroke for a Ϊ or Ϋ.

This assumption is supported by standard keyboard layouts for Greek, which are based on typewriter conventions, and do not anticipate case conversion issues. Not surprisingly, the basic Unicode Greek set has only one form of  Ϊ or Ϋ at U+03AA and U+03D4 respectively. The extended Unicode Greek set also does not provide “double” Ϊ or Ϋ.[1. It is arguable that this is a semantic distinction, and not a stylistic one, but it is unlikely that Unicode would be amended in this respect. Therefore, the distinction must be maintained within the font file, and supported by the typesetting environment.]

Roundtrip conversion is a constant issue in Greek; it applies throughout this discussion.

 

Initial accented letters

The easiest way to understand case conversion complications in Greek is to think of accented letters having three cases, instead of two:

– lowercase accented leters, where the accented letter and its neighbours are also lowercase;
– initial-case accented letters, where the letter with an accent is a capital but its neighbours are lowercase; and
– uppercase, where only the dieresis is visible, and the accented letter and its neighbours are all capitals.

Here is an example:

Έλα Άννα! Ήρθε η ώρα. 
Ύστερα θα είναι αργά.
Όταν πάμε σπίτι θα καλέσουμε την Ήρα.

These sentences should convert to:

ΕΛΑ ΑΝΝΑ! ΗΡΘΕ Η ΩΡΑ. ΥΣΤΕΡΑ ΘΑ ΕΙΝΑΙ ΑΡΓΑ.
ΟΤΑΝ ΠΑΜΕ ΣΠΙΤΙ ΘΑ ΚΑΛΕΣΟΥΜΕ ΤΗΝ ΗΡΑ.

Note that all the accents in initial capitals disappear. This is the correct behaviour; any deviation is wrong. So, for example, the Foursquare Greek maps and the Wordpress comment form below are wrong:

(This behaviour is not limited to these platforms; it generally happens when a CSS style capitalises text strings that have been keyed in as twin-case.)

 

Let’s modify our example to include a dieresis:

Έλα Άννα! Ήρθε η ώρα. 
Ύστερα θα φύγει το καΐκι.

Όταν πάμε σπίτι θα χορέψουμε ζεϊμπέκικο.

These sentences should convert to:

ΕΛΑ ΑΝΝΑ! ΗΡΘΕ Η ΩΡΑ. ΥΣΤΕΡΑ ΘΑ ΦΥΓΕΙ ΤΟ ΚΑΪΚΙ.
ΟΤΑΝ ΠΑΜΕ ΣΠΙΤΙ ΘΑ ΧΟΡΕΨΟΥΜΕ ΖΕΪΜΠΕΚΙΚΟ.

Note that the dieresis survives the conversion, as it should. But keep in mind that the highlighted letters are not like the rest of the capitals, since they must ‘gain’ an accent when converted back to lowercase:

ΕΛΑ ΑΝΝΑ! ΗΡΘΕ Η ΩΡΑ. ΥΣΤΕΡΑ ΘΑ ΦΥΓΕΙ ΤΟ ΚΑΪΚΙ.
ΟΤΑΝ ΠΑΜΕ ΣΠΙΤΙ ΘΑ ΧΟΡΕΨΟΥΜΕ ΖΕΪΜΠΕΚΙΚΟ.

It is possible to come up with simple rules to predict that behaviour, for example:

[space]+Ά/Έ/Ή/Ί/Ύ/Ό/Ώ+[class with all lowercase letters]
convert to:
[space]+Α/Ε/Η/Ι/Υ/Ο/Ω+[uppercase letters]

but the roundtrip is not so straightforward. For this to happen, the capitals that the accented initials convert to must be different than the ‘plain vanilla’ ones. In other words, the font must include multiple instances of unaccented capitals, addressed through OpenType features. (Using CIDs in this case means that the words will never degrade gracefully in an environment that does not read the feature: either they will lose the accent, or convert to a lowercase form amongst uppercase ones.).

 

Dipthongs and double vowels