diff --git a/src/lang/english.txt b/src/lang/english.txt
--- a/src/lang/english.txt
+++ b/src/lang/english.txt
@@ -1065,6 +1065,7 @@ STR_CITY_APPROVAL_PERMISSIVE            
 STR_CITY_APPROVAL_TOLERANT                                      :Tolerant
 STR_CITY_APPROVAL_HOSTILE                                       :Hostile
 
+STR_WARNING_NO_SUITABLE_AI                                      :{WHITE}No suitable AIs available...{}You can download several AIs via the 'Online Content' system
 STR_WARNING_DIFFICULTY_TO_CUSTOM                                :{WHITE}This action changed the difficulty level to custom
 
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