I have been teaching English for almost eight years for Egyptian university students at the English Department. Out of my experience of teaching Phonetics and Phonology for those students, I can conclude that the Egyptian learners of English encounter many pronunciation problems because of two main reasons: the English spelling as a poor reflection of the English pronunciation as well as the differences between the Arabic phonetic alphabet and that of English. Examples of such problems are to be classified and highlighted under each of the above reasons.
To start with, as for the English orthography, there are twenty-six letters to represent almost twenty vowels and twenty-four consonants, which is not the case in Arabic where each letter represents one sound only and each sound can only be represented by one letter. Also, in Arabic, there only three vowels and the rest of the phonemes are consonants. Accordingly, when it comes to English, the Egyptian learner is surprised to find, for example, letter pairs used instead of single letters to represent a single phoneme such as "sh" and "oa", which gives rise to confusion when they are not taken as a pair as in bishop and moan.
Another inconsistency is that the same letter or group of letters does not always represent the same sound in English. Some letters can stand for as many as four different sounds. For instance, the letter "c" has no sound equivalent as /c/; it is realized as /k/ as in cup and /s/ as in cellular. The learner cannot predict in which word "c" is pronounced as /k/ or /s/. In contrast, the same sound is not always represented by the same letter or group of letters. Such examples are the /f/ sound which is spelt as "f" as in fit, "ff" as in offer, "gh" as in tough and "ph" as in photo as well as the /e/ sound which is realized in various spellings like "a" as in many, "aI" as in said, "e" as in let, "ea" as in dead, "eo" as in leopard, "ie"