If you write any foreign names in the author field (and presumably the editor field, although I’ve not tested this) in your bibliography (.bib) file using babel‘s \foreignlanguage
command, make sure you \protect
it:
@BOOK{key,
AUTHOR = {\protect\foreignlanguage{spanish}{Cruz, Ana}},
…
}
For some reason I cannot explain, using the \foreignlanguage
command generates errors in the .bbl file output by BibTeX, particularly if you have the name Llorenç, but I have no idea why. If you do and know how to fix it, please let me know in a comment!