diff --git a/v2/i18n/localizer.go b/v2/i18n/localizer.go
index 17261e2e..1a594556 100644
--- a/v2/i18n/localizer.go
+++ b/v2/i18n/localizer.go
@@ -9,6 +9,9 @@ import (
 )
 
 // Localizer provides Localize and MustLocalize methods that return localized messages.
+// Localize and MustLocalize methods use a language.Tag matching algorithm based
+// on the best possible value. This algorithm may cause an unexpected language.Tag returned
+// value depending on the order of the tags stored in memory.
 type Localizer struct {
 	// bundle contains the messages that can be returned by the Localizer.
 	bundle *Bundle