Manual:$wgLangObjCacheSize

Language, regional and character encoding settings: $wgLangObjCacheSize
Language cache size, or really how many languages can we handle simultaneously without degrading to crawl speed.
Introduced in version:1.21.0 (Gerrit change 35124; git #121cf601)
Removed in version:1.37.0 (Gerrit change 709227; git #b98cca88)
Allowed values:(integer)
Default value:10