Language detection 

Solr uses the langid UpdateRequestProcessor to identify languages and then map from text to the language-specific field while indexing.

There are two implementations provided by Solr for language detection: 

• Tika language detection
• Langdetect language detection

Language detection configuration

The configuration for language detection is done in solrconfig.xml and both Tika as well as langdetect language detection use the same parameters, as follows:

<processor class="org.apache.solr.update.processor.TikaLanguageIdentifierUpdateProcessorFactory">
    <lst name="defaults">
        <str name="langid.fl">title,subject,text,keywords</str>
        <str name="langid.langField">language_s</str>
    </lst>
</processor>
<processor class=
"org.apache.solr.update.processor.LangDetectLanguageIdentifierUpdateProcessorFactory">
    <lst name="defaults">
        <str name="langid.fl">title,subject,text,keywords</str>
...