Diacritics, or tone marks (as what they're called in my language), are symbols added to letters to change their sound. For example, diacritics for the letter a in my language can be ă, â, à, á, ả, ã, ạ, ắ, ẳ, etc.
What should I do with papers written in such language when citing them in an English context?
For example, the APA Style guide says:
Book/article titles and names written in Latin-based scripts (French, Spanish, German, etc.) can be cited with only minor adjustments.
My language (Vietnamese) uses Latin script, so logically, I should preserve the diacritics. However, I think the guideline is only aware of Western languages, which may not have so many diacritics. If I follow the guideline, the title of my work may be cited like this:
So sánh năng lượng liên kết tĩnh điện giữa các thể đột biến của protease HIV-1 khi liên kết với thuốc lopinavir (Compare the Electrostatic Energy between Mutants of HIV-1 Protease when binding to lopinavir)
Is there any problem if I keep the diacritics? I think the title will only be copy-pasted, so there is no big problem if I cite it like that. It may be hard for foreign readers to read, but I think they wouldn't care at all; there is a translation of it in the bracket anyway. A common practice is to "transliterate" it to a non-diacritic version, which can be typed in any unsupported keyboard, and that is readable to the native speakers. However, it will make a lot of adjustments, and regarding to the guideline, this should only be used for non-Latin scripts.
I choose the APA style because it is the first thing come up in my mind. I think other styles will recommend the same. Some other styles suggest that I just need to provide the translation, but that is the easy case.
Nowadays, every sufficiently recent typesetting system is able to deal with diacritics. When submitting to journals, the real problem are the publishers' typesetters, who are -- at least in my experience -- frequently careless in copying letters with diacritics.
So, my advice is: keep the diacritics, as the style guides and common sense suggest, but check carefully the proofs received from the publisher.