The extended Latin script has full coverage for many languages:
English, French, Spanish, German, Italian, Breton, Catalan, Danish, Estonian, Finnish, Icelandic, Indonesian, Irish, Lojban, Mapudungun, Norwegian, Portuguese, Scottish Gaelic, Swedish, Tagalog
Some languages are only partially covered:
Azeri, Croatian, Czech, Esperanto, Hungarian, Latvian, Lithuanian, Polish, Romanian, Serbian, Slovak, Slovenian, Turkish, Yoruba, Welsh
Some languages have little or no coverage:
Arabic, Bulgarian, Cherokee, Dzongkha, Greek, Hindi, Macedonian, Malayalam, Mongolian, Russian, Sanskrit, Thai, Tibetan, Urdu, Uyghur
The following variable declarations are all valid:
Dim Yec’hed As String 'Breton Dim «Dóna» As String 'Catalan Dim fræk As String 'Danish Dim tšellomängija As String 'Estonian Dim Törkylempijävongahdus As String 'Finnish Dim j’examine As String 'French Dim Paß As String 'German Dim þjófum As String 'Icelandic Dim hÓighe As String 'Irish Dim sofybakni As String 'Lojban (.o’i does not work) Dim ñizol As String 'Mapudungun Dim Vår As String 'Norwegian Dim «brações» As String 'Portuguese Dim d’fhàg As String 'Scottish Gaelic
Note that in the VBA IDE, a single apostrophe within a variable name does not turn the line into a comment (as it does on Stack Overflow).
Also, languages that use two angles to indicate a quote «» are allowed to use those in variable names desipte the fact that the ""-type quotes are not.