My native language is Arabic. However, after doing some research on the subject, I believe that the origin of Arabic language and the scriptural Hebrew language is very similar and used initially the same phonics for the letters subject of this discussion. However, these letters are very hard to pronounce for other nations from a non Semitic origin, or for those individuals or groups who were raised in Western countries, and so the letters were replaced by their nearest phonic substitutes.
1-So, letter (ע) for example is the strict equivalent of the Arabic letter ( ع). This phonic does not exist in any other language I know of (and I speak a few). So, the nearest possible substitute would be the vowel [a] to be used as a consonant.
2-A second example is the letter ( ק ) which is the strict equivalent of the Arabic letter ( ق), but because there is no other group of languages that use this phonic, it was replaced by the consonant (כ-ך ) [k].
3- A third example is the letter ( ח ) which is the equivalent of [ خ]. Fortunately, this letter exists in other languages as well such as Spanish, German, UK and Irish Gaelic, etc. If it happens that you know the singer Julio Iglesias, this phonic exists in the first letter of his first name (julio), pronounced by Spanish people (Europeans don't know how to pronounce his name at all).
Arabic as it's spoken today is just a continuation of a more ancient root such as Aramaic, Amharic, classic Hebrew, etc. These languages were truly one language with different dialects but are perceived nowadays to be different in essence because of political and religious reasons. Thus if your aim is to learn classic Hebrew, then my advice is to copy the sounds of Arabic speaking Israeli. However, if your aim is to learn modern Hebrew to get by in Israel, then it's more practical to copy the way the majority in your circle speak.
I hope this helps.