Go verb first. (Usually.)
Buttons do not follow usual expectations of writing, but there are a few basic guidelines that foster good button design. Here I'm going to paraphrase two bits of advice from UX Booth that I use when teaching visual rhetoric:
- No friction: the label should be quickly understood
- Verb first: begin with the verb. A button does something. The verb describes the action.
Have I seen buttons that are noun first? Yes. Your keyboard likely has a caps lock key, where the verb (lock) comes second. However, most labeled keys are either verbs or can be used as verbs (delete! backspace! enter! page up! escape!). I'd only put the verb second if I have a great reason to do it and if it causes no misunderstandings.
Otherwise, and especially in situations where your users have not acclimated to a standard format, the verb gives users a clue for what it does. The noun, as necessary, names what that verb affects. So:
- Analyze Route (the button analyzes something. what? a route. good.)
- Alert Mute (the button alerts something. what? a mute. that can't be right.)
- Mute Alert (the button mutes something. what? an alert. great.)
As a general guide (again going back to the article), imagine you're asking, "What do I want to do?" The answer is, "I want to ______." Analyze the route, mute the alert. The verb comes first. If it helps you get over the sense you're commanding your readers, view it as a bare infinitive (an infinitive lacking "to") following an implied "I want to" rather than a verb in the imperative mood. In any case, that verb will still tend to make the function of your button clearer. To drive this point home one more time, here's another article on UX design in buttons:
Write button labels that clearly explain what each button does. Ideally, the button’s label should clearly describe its action.
The verb is the action. Now I'm going to click "Post Your Answer."