Do I understand you right, that Arabic uses diacritics when written in Arabic script? Or did you mean Arabic when written in Latin script?

Using diacritics is usually a sign, that the language uses a script that does not map very well to the target language, so the latter would be understandable.

Slavic languages would the same in this regards. Those, that are written in Latin script, have to use diacritics. Those that use Cyrillic, do not need to.

All Cyrillic alphabets I am aware of do use diacritics. Й, Ў, Ё, Ґ..

While you are of course right, that there exist such characters, Belorussian and Ukrainian are not all Cyrillic alphabets.

But then, I'm also not an expert on all Slavic languages, I just remember when I was taught Russian and azbuka years ago, there was none and that caught my attention.

> Belorussian and Ukrainian are not all Cyrillic alphabets.

LOL Please, tell us an «all Cyrillic» alphabet. Old Church Slavonic by Saints Cyril and Methodius maybe?

Why Belorussian and Ukrainian are «not all Cyrillic alphabets»? (I'm Ukrainian).

There's the difference between 'some' and 'all'. Ukrainian and Belorussian are 'some', not 'all'.

Language may have some local specifics - Serbians have Ћ, which all other Cyrillic-using languages do not have. You have І instead of И, etc.

Й and ё are in Russian alphabet. In schools it is never highlighted that those are diacritics, so to many it doesn't register.

Are those diacritics? I tend to think of them as separate letters just as å and ä are separate letters in Swedish. Of course, ё is usually written as е so I may well be wrong about that.

This is different from è, é, ë, and ê in French where these are all e, but with different diacritics.

That's my impression of the statement as well. Even if technically they can be called diacritics it doesn't make much sense, not within this discussion. "Й" sounds absolutely unlike "и" and has pretty much no connection to it. "Ё" is a bit more tricky, but nevertheless — there's no another letter in Russian alphabet we could put umlaut on and get the result similar to putting umlaut on "е".

I guess "ь" has more right to be called diacritic, because it genuinely has 1 purpose: altering the other sounds. But even that is treated as a separate letter.

It's nothing like diacritics in French, German or even Latvian, let alone Arabic.

Й is absolutely linked with и, and it arose as alphabetic distinction from it. It appeared and disappeared for certain periods; in Russian it reestablished as a letter only in 20th century. It is still commonly collated with И in indexes and dictionaries.

> "Ё" is a bit more tricky, but nevertheless — there's no another letter in Russian alphabet we could put umlaut on and get the result similar to putting umlaut on "е".

This is a bizarre distinction: diacritics in natural languages aren't supposed to be freely recombinable.

Those letters use no diacritics. They are just letters.

These are the letters with diacritic marks.

No. іе -> ё, іі -> ї, иі -> й. оу -> ў. They are just shortened, to write less.

Well, ў for once is not a shorthand for оу (e.g. слаўны, ўзяў). But it's beside the point, all diacritics are used to "write less".

> But it's beside the point, all diacritics are used to "write less".

That may be the reason for misunderstanding. In my language (Slovak), diacritic is not used to "write less". It is used to express different sounds, i.e. s = с, š = ш, c = ц, č = ч.

Sure, but just as you demonstrate you have fewer distinct characters when you use diacritic than when you don't. And arguing whether Е and Ё are same character with diacritics, or just different letters that happen to have diacritics by the virtue of canonizing in alphabet is really splitting hairs. They serve same purpose, in the same circumstances, with the same visual arrangement. Quacks like a duck etc.