The adverb for the adjective ‘hard’ is simply ‘hard’. Have a look at these examples:
The exam was very hard. (adjective: hard=difficult)
I worked very hard to pass my exams. (adverb: to work hard= to put a lot of effort)
When used with words like ‘anything’, ‘anyone’ etc ‘hardly’ means ‘almost nothing‘, ‘almost no one‘:
He hardly said anything at the meeting >> he almost said nothing at the meeting
Hardly anyone talked to me at the party >> almost no one talked to me
Notice that ‘anything’ and ‘anyone’ are used in the above examples because ‘hardly’ is a negative word and English doesn’t allow double negatives:
He hardly said
nothing anything at the meeting
Generally speaking ‘hardly’ makes a sentence (almost) negative:
She hardly speaks French >> She almost speaks no French (or She speaks very very little French)
I can hardly understand British people when they speak >> I almost don’t understand them (or I understand very very little)
Notice the adverb position: ‘hardly’ comes before the main verb (speak) but after modals (can).
‘Hardly ever’ is used when talking about the frequency of an action and it means ‘almost never‘:
I hardly ever go the gym = I almost never go to the gym (or I very rarely go to the gym)
I hardly ever see him nowadays = I almost never see him nowadays (or I very rarely see him)
So pay attention when talking about how hard you’ve worked as you might end up saying quite the opposite:
I’ve worked really hard= I’ve really put a lot of effort / I’ve worked a lot
I’ve hardly worked= I’ve put almost no effort / I’ve worked very little
Notice the adverb position: hardly goes just after the auxiliary ‘have’.
Hope this post has shed some light on the difference between ‘hard’ and ‘hardly’!