Although by default Acquia Search's schema is optimized for English searches, Acquia also provides schemas in other languages. Because most of these languages are Latin-based and have many grammatical and vocabulary similarities, they can be used in a relatively straightforward fashion.
There are other languages however, such as Chinese, Japanese, and Korean (CJK), that use different stemming and spacing rules than Latin-based languages, which causes the Solr / Lucene search engine to handle them differently.
You can add support for these languages by using a custom Acquia Search Solr configuration.
For additional background information regarding CJK languages, see the following resources: