There is currently no out-of-the-box feature to index records in multiple languages. As a workaround, you can create a separate product for each language and add that product to the channel.
BigCommerce recently released a Markets Beta feature that allows a single product to store multiple languages. This feature is not yet supported by Algolia; we are tracking user demand for indexing the Markets Beta into Algolia and may consider supporting this feature in a future release.