diff --git a/zanata-war/src/main/resources/messages.properties b/zanata-war/src/main/resources/messages.properties
index 2c23e611f7..7fb81cda95 100644
--- a/zanata-war/src/main/resources/messages.properties
+++ b/zanata-war/src/main/resources/messages.properties
@@ -1389,8 +1389,10 @@ javax.faces.converter.BigDecimalConverter.DECIMAL=value must be a number
 javax.faces.converter.BigDecimalConverter.DECIMAL_detail=value must be a signed decimal number consisting of zero or more digits, optionally followed by a decimal point and fraction, eg. {1}
 javax.faces.converter.BigIntegerConverter.BIGINTEGER=value must be an integer
 javax.faces.converter.BigIntegerConverter.BIGINTEGER_detail=value must be a signed integer number consisting of zero or more digits
-javax.faces.converter.BooleanConverter.BOOLEAN=value must be true or false
-javax.faces.converter.BooleanConverter.BOOLEAN_detail=value must be true or false (any value other than true will evaluate to false)
+# Please do not translate 'true' or 'false'.
+javax.faces.converter.BooleanConverter.BOOLEAN=value must be 'true' or 'false'
+# Please do not translate 'true' or 'false'.
+javax.faces.converter.BooleanConverter.BOOLEAN_detail=value must be 'true' or 'false' (any value other than 'true' will evaluate to 'false')
 javax.faces.converter.ByteConverter.BYTE=value must be a number between 0 and 255
 javax.faces.converter.ByteConverter.BYTE_detail=value must be a number between 0 and 255
 javax.faces.converter.CharacterConverter.CHARACTER=value must be a character