Salam Alakum, It is complicated for the first time, and you will notice it is quiet easy to get the sounds of ح and هـ هــ sounds as in Holiday The second one ح I let you see this picture : http://www.m5zn.com/uploads/2010/2/10/photo/gif/3dlmo6fx01.gif it will be more clear than explaining by words. Also, you can watch this video about the alphabet's sounds: https://www.youtube.com/watch?v=aMv7HB2xbVs Good luck

the two letters are completely different , but because (ح) Does not exist in English , English native speakers Pronounced it like (ه )

Yep totally different ... you must hear very well the pronunciation ... https://www.youtube.com/watch?v=xqQkxf6XMQU

Yes, these two letters are exactly different letters and it's pronunciation also different. The source of the sound is different. For example:- محمد ، نصيحة ، حق (truth, advise and a person's name) هدى ، هم ، قهوة ( coffee, grieve and right path ) Only through conversation or watching some Arabic program, you can understand the difference.