Hardly x Hardly ever: Qual a diferença

Existe alguma diferença entre os advérbios Hardly e Hardly ever?

Hi there!

Ambos são advérbios e, portanto, irão complementar um verbo / adjetivo. Veja:

Hardly adverb
​Only just or almost not:
Hardly a day passes that I don’t think about it.
You’ve hardly eaten anything.
Something is wrong with the phone – I can hardly hear you.
I can hardly wait for your visit.
We hardly ever see them anymore.

From: Cambridge Dictionary

hardly ever
Phrase
Very rarely.
We hardly ever see them.

From: Oxford Living Dictionaries

Ex.:
"Hardly" = pobremente, escarsamente, mau (no sentido de quase não).

"Hardly ever" = denota frequência: muito raro.

Exemplos:
"I hardly know how to speak English."
"We hardly ever go to concerts."

Cheers!