Hooks let you change any of the messages displayed by Liferay, to suit your
needs. To do so, create a Language file for the locale of the messages you
want to customize, then refer to your file from your liferay-hook.xml file.
For example, to override the Spanish and French message translations of portal’s
Language.properties file, create Language files for them in the same
directory, and refer to these language files in your liferay-hook.xml file,
like so:
<hook>
...
<language-properties>content/Language_es.properties</language-properties>
<language-properties>content/Language_fr.properties</language-properties>
...
</hook>
Great! You now know how to customize language keys. Next, let’s discuss extending your Indexer Post Processor.