Earlier, you might have used the Display language menu setting to give your users a list of languages for the site. When a user selects one of these languages, only the Moodle interface is translated. The course content remains in whatever language you created it. If you want your site to be truly multi-lingual, you can also create course content in several languages. Activating the Multi-Language Content filter will then cause the course material to be displayed in the selected language.
To create course content in multiple languages, you must enclose the text written in each language in a <span> tag, as follows:
<span lang="en" class="multilang">Basic Botany</span> <span lang="es" class="multilang">Botánica Básica</span> ...