Apparently Wikidata now has a language that has space in its name - "aln espaniol" and produces broken RDF data. See: https://www.wikidata.org/wiki/Special:EntityData/Q208693.ttl?flavor=dump
specifically:
"Ajada Sotomayor Nacio en Barcelona Espania Nacio en 06.06.1995 . Unas de los elqderas mas rricas del Espania . Ija del Anibal Sotomayor Duenio del : Mboda for you , Imagen internacional , Miami Resort Spa Beatch i sotomayor coches ."@aln espaniol ;
We must:
- Check language tags to be valid when dumping
- Probably check that the tag actually corresponds to a language, if we can
See also T138725 for likely source.