The most recent MARC records files from NLS included several titles that are either bilingual or have some ambiguity in the record as to the primary language. Please review these titles (listed below) to ensure that the Language is set to how you want Nightly to treat the titles.
Remember that Language must match for all Nightly programs other than Request or Reserve. A language code of "ENG/SPA" will not match either "ENG" or "SPA", only "ENG/SPA", so you need to pick one or the other. A subject heading of Bilingual may be used to help identify these titles, but they will only be sent by Nightly to patrons with a match for the language set on the Title-Bib tab.
Titles to review:
DB 110318 is a bilingual Spanish/English book marked by NLS as English in the 008
DB 115095 is an English children's book with Spanish words about Arroz con Leche, marked SPANJF in the 072 and ENG in the 008
DBC27063 -- 008 says ENG, 072 says SPANAN - it is originally written in Spanish, but is an English translation
DBC26930 -- 008 says Spanish, 072 says Spanish, other data elements suggest both Spanish and English or more English, originally written in Spanish
For those of us less familiar with MARC or NLS' cataloging standards: 008 always contains a language code from NLS, which KLAS uses to set the Language on the title-bib; 072 is the genre code with four characters, A for adult or J for juvenile, then F for Fiction or N for Non-Fiction. So SPANJF=Spanish Juvenile Fiction.
BR 25018 - 008 = ENG; 072 = SPANJF; Print Braille; 546 = Text in English, with Spanish words.
BR 25062 - 008 = ENG; 072 = SPANJF; 546 = Parallel text in English and Spanish.
DB 115721 - 008 = ENG; 072 = SPANAN; 546 = Bilingual Spanish and English.
546 is the designated MARC tag for a "language note."
Additionally, NLS has added a new 655 (genre subject heading) tag for "Bilingual Books", but there seems to be some inconsistency in how it's applied (See BR 25020, BR 25024, and BR 25018)