Unlike single-language websites where all of the site content and administrative interfaces are operating under a single language, multilingual sites allow visitors to pick their language while viewing the website.
The most popular plugin for WordPress multilingual sites at the time of this writing is WPML.
Store Locator Plus has begun the journey into supporting multilingual sites with WPML. Changes to WPML in late 2015 will require further revisions to the WPML compatibility layers.
Since version 4.3.06 Store Locator Plus added features that will help the plugin and add-on packs communicate with WPML for user-configurable translation strings. While the entire fixed-text portion of Store Locator Plus uses gettext, a common language translation utility, there are many strings that appear as user-configurable settings. Options such as search and results labels fall into this category.