Hi Haklae,
Yes, if you want to query for an abstract in a different language,
simply change EN to another two letter language code (eg, FR for
French).
If you remove the FILTER ( langMatches(lang(?abstract), \"EN\") )
altogether, you will get the abstract in all available languages, and
you can examine the results to see what language codes are used.
If you want to match a precise language code in the data (eg: en-gb is
British English), your filter can be like:
FILTER(lang(?abstract)="en-gb")
however if you want to match any variant of a language (in this case,
English), you can use langMatches:
FILTER( langMatches(lang(?abstract), "EN") )
(this will match literals with languages including en-gb, en-us, en,
en-ca, en-au)
for further details see
http://www.w3.org/TR/rdf-sparql-query/#matchLangTags
and
http://www.w3.org/TR/rdf-sparql-query/#func-langMatches
HTH
Keith