Hola,
I'm new on this forum, but I read all the reactions here and I couldn't help but to make an account and share my thoughts.
I'm dominican myself and a language lover. I grew up speaking Dutch, English and Spanish and have been learning French and Lation for over six yours now in high school. I also studie quite some languages and linguistic subjects in my spare time.
As some of you may know the Spanish language is part of the Romance Language Family and as such has genetic similarities to languages like French, Italian and Portugues. All these languages come from Vulgar Latin. Latin was a language spoken by many peoples in Europe during the Roman Empire and developed into different languages in different places. That's why when one who speaks Spanish studies these languages, he will notice a remarkable ressemblence between them in grammar, vocabulary and syntaxis.
This is just to show you guys that I know what I'm talking about. As for the 'not so silent h', here it comes.
One thing I love about having studied Latin is knowing now where Spanish comes from and I now know what the etymology is for most words ( 'eternidad' comes from 'aeternitas', 'padre' comes from 'pater' and 'siglo' from 'saeculum' and I can go on for hours.) and the origin of most syntactical and grammatical constructions.
As for the silent 'h'. The silent 'h' was still being pronounced in Middle Spanish. And it came from words that began with an 'f' (this has not happened to the same words in French, Italian and Portuguese, that's why in cognate words (words with the same etymological origin) in these languages you still see the 'f'). 'hablar' comes from 'fabulare' (telling stories > talking - think of Portugues 'falar'), 'hacer' comes from 'facere' (to do> maybe now you start thinking about French 'faire', Italian 'fare' or Portugues 'fazer' ). Other exemples are : hoja > folia (french : foeil, italian : foglia) and hijo > filius (french : fils, italian : figlio and Portuguese : filho) The 'f' lost it's strong pronunciation in word-initial positions and so came more to be pronounced like an 'h' or jota. (Another beautiful exemple is 'hecho' what comes from 'factum' wich means 'something that has been done (that's true)' > a fact (the English word 'fact' also has this origin.) Later on this h-sound disappeared but the 'h' was still written
The Spanish that came to the Carribean is Andaluz Spanish that still had, in the period it came to RD, a lot of archaic caracteristics and so in that region the 'h' sound was still being pronounced in word-initial position. When you read books or threads or studies on Dominican Spanish you will often read that one of the caractaristics of Dominican Spanish is the use of archaisms, even though this has been diminishing. Think of words as 'cuarto' and a lot of others. So the use of the pronounced 'h' is an archaic feature, that in most words of Latin origin is still a mark of the old 'f' and ofcourse when the 'h' was being pronounced, people may have figured that words like 'hamaca' that does not have a Latin origin were also to be pronounced with a not so silent 'h'. So it's mostly due to historical factors and ofcourse social factors.
I hope some of you can appreciate this information, don't know if someone's gonna see this, 'cos I see here this thread has been abandoned for quite some time.
Que queden con Dios todos y buenas noches