# Polyglossia vs Babel

Could someone summarize features which are (1) common and (2) different for the `babel` and `polyglossia` packages? I know that `babel` 3.8 (current version) fails to run for some languages (eg, Russian) under LuaLaTeX and XeLaTeX (at least it was so 2 years ago). What will be the future of the `polyglossia` package if `babel` 3.9 (which is now `babel-alpha`) will manage to work with XeLaTeX? Will be any sense to use `polyglossia` as a replacement of `babel` in that case?

UPDATE: I am sorry for mixing several questions in one post. Main question was about differences between `polyglossia` and `babel`. For example, `polyglossia` has options specific to some languages.

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The relationship between `babel` and `polyglossia` with respect to XeTeX is complicated. The general rule of thumb is that if the babel `.ldf` file uses non-Latin scripts, then you should use `polyglossia` and generally can't use `babel` but if it assumes Latin scripts, you may still be able to use `babel`. With respect to your specific question, about Russian, it's obviously possible to write `babel` `.ldf` files that work with both engines, but for most of the non Latin scripts, this will not have been done and `polyglossia` will still be required.

The issues with Cyrillic are arguably less complicated than those using RTL scripts such as Hebrew and Arabic (as alluded to in @egreg's comment). Other scripts such as for Hindi also pose special problems for which pdfLaTeX is unlikely to be a choice. So `polyglossia` will remain required for those scripts which independently depend on XeLaTeX.

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Moreover, `bidi` integrates with `polyglossia` –  egreg Dec 29 '12 at 15:29
Indeed. such Russian.ldf has been already written. See ctan.org/pkg/russian. –  Igor Kotelnikov Dec 29 '12 at 16:36
Can you use both? Suppose that you wanted to write a document in Welsh about Hebrew, for example. Welsh requires babel but Hebrew requires polyglossia. Or is this kind of combination just not supported? –  cfr Jan 2 at 21:06

As far as I know, `polyglossia` is intended to be a replacement of `babel` for `XeLaTeX`.

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But why I would need `polyglossia` if `babel` will work with `xelatex`? In particular, the new russian LDF (ctan.org/pkg/russian) makes it possible to use `babel` with either of the existing latex engines, including xelatex. –  Igor Kotelnikov Dec 29 '12 at 15:07
@Igor Kotelnikov: who knows what will happen? the current work aims to process the (large) backlog of babel error reports. whether this work will leave us with a babel that works with unicode input (and things like bidi) remains to be seen. so your question is (as yet) not answerable, i fear. –  wasteofspace Dec 29 '12 at 21:33