pH, and not ph (nor Ph.D) is the way to measure acidity. It is a measur of the proportion of H+ ions in the solution. The more the lower the pH and the more acid the solution is (go to the wikipedia for more detailed answer). HCl release H+ in the solution, making it acidic. An acid pH is a pH value smaller than 7.
So waht your sentence means is that the environment is acidic (as you said because of the HCl in solution) and that is what stimulates the secretion of those hormones (provided what you say is true, I know very little about that). But would the HCl be neutralized by an alkalinic compound, it would still be here, yet the pH would not be acidic and the hormones not secreted.

And for the liver, I think some is false (bile is not produced in the liver) and you missed some of the most important functions. But once again, the wikipedia will be much more knowledgeable tha I am on the subject

The presence of chyme (in acidic condition because of the presence of HCl) in the stomach stimulate the release of secretin, gastrin and cck that control digestive secretion.
Liver does produce bile which is the byproduct of hemoglobin breakdown that occur in it. It also produces blood protein and lipoproteins but NOT digestive enzymes. Enzymes are from the pancreas and the in testinal glands.
Sham

Shame on you Patrick. Yes, it is true, the liver does produce bile. Bile contains water, ions, biliar pigments(bilirubine, biliverdine – they come from the breakdown of haemoglobine), biliar salts and acids, lectine, phospholipids. As said before, there are no enzymes prezent in bile.
And i agree, the sentence about hormones is true…

I accept the shame. One more reason to hate eucaryotes, they are too complicated for my simple brain. I go lacerate myself with fresh thorns.

But I maintain that liver functions are not limited to those described in th eoriginal poster sentence.

Oh yes, the liver has more than 50 identified functions and counting..