Currently the Browser --> Language option when creating audiences only supports specific browser languages. Targeting "English" language browsers only works when 1) the user's browser language is set to "English" NOT "English (United Kingdom)", "English (United States)" etc OR
2) "English" is at the top of the list in the user's list of browser languages
This specificity significantly restricts the targeting ability, and it would be nice to have an option to support all the browser languages using the Target UI.