What does it mean to "aspirate words"?

I was looking at the script for the 1895 theatrical adaptation of “Dr. Jekyll and Mr. Hyde” and noticed it has this to say about Hyde:

So, what exactly, does the bolded mean? I googled it but can’t figure it out.

Breathy. Think Marilyn Monroe’s “Happy Birthday, Mr. President”

It means to say with an “H” sound. The difference between the word “ate” and the word “hate” is that “hate” is aspirated. What you quoted indicates that the speaker tends to continually exhale noticeably when speaking.

And at the very least means that he doesn’t drop the initial aspirate on words like “happen” and “home” and isn’t to be played as a conventional comical lower-class stereotype.

Here’s the use of the term back in 1821 describing a character in a play. It must have been a well recognized affect in Victorian England.

In English, we aspirate letters like ‘P’ and ‘T’. This isn’t done in many other languages. To get an idea of how that sounds, try saying the word ‘pop’ without expelling breath. This is part of the reason why non-native English speakers, such as those from the Indian subcontinent, sound odd to us.

As an exaggerated example, think Gollum in LotR movies.

Think of Darth Vader.

There is a class of English speaking people who aspirate words where the initial ‘H’ is normally silent. It is generally accepted that dropping aitches, as when “Give him a hug” comes out as “Givimm anug”, is a clear indication of a lack of education. A few people will overcompensate, adding them where they don’t exist. "“Hit’s a nice day, hisn’t tit”.

ln Hertford, Hereford and Hampshire hurricanes hardly ever happen…

(an English Cockney’s explanation of How To Become Very Famous)
by Edwina May

From some ask-any-question site:

So be very careful not to aspirate your words. You could choke and suffocate on them.

Because Mr Hyde is changing the voice from a regular mans voice, the script writer, and hence the actor, must have chosen a voice a regular man could successfully put on…

There’s only one… hence the list of characters you see already… and of course so many more…

This is the squeaky, poorly projected (no boom to it), nasal , “aspirated” voice…
So the aspirated syllables are what come across… the nasal tone accentuates the vowels (gutteral consanents are weak if speaking nasally …) , the S’s and others are lisped (insufficiant blockage of flow of air…)
and other examples toward aspirated…

It doesn’t mean purely aspirated… it means more aspirated…