localization of validators in angular 7 reactive forms #6794

angular, dotnetcore, 6.8.0, .net 4.6.1 I have a validation message in an angular reactive form:

{{l("RequiredField", l('Surname'))}}

How do I use the localize pipe for both values? I can localize the second field but not the first:

{{l("RequiredField", 'Surname' | localize)}}

works. But

{{'RequiredField' | localize, 'Surname' | localize)}}

does not. Any ideas anyone?