Hello all,
There has been a post on the Bulgarian section of the OSM forum that Bulgarian names are not correctly transliterated (https://forum.openstreetmap.org/viewtopic.php?id=73331). According to these users, names show as question marks or if they show up the transliteration is incorrect. Here are some examples:
Драгоман - Draghoman instead of Dragoman
Драговищица - Dragovishchica instead of Dragovishticha
Петърч - Pet?rch instead of Petarch
I've found a document that shows what the correct transliteration of each letter is. It is complient with the transliteration act as of its last change in 2019. Note that it only applies to the Bulgarian language. Other languages may have different rules
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/811509/ROMANIZATION_OF_BULGARIAN.pdf
Is it possible to fix this issue without causing issues for other Slavic languages? I haven't investigated how your software works, but a possible solution could be to have a different set of rules for each country.
Regards,
Dimitar