Most inner city schools have pupils where English is not there first

Sometimes change the situation around by building confidence. Breakdown the learning experience.   Ask first how a certain phrase is said in Arabic, that they will know, then select key words or phrases for the student to say in English.  Ensure they understand the word/ phrase and what is expected from them, don't let them struggle just because they are in the minority in the class.  In fact, see this as an opportunity to improve all students English and not just single out non-English students.  Relate words and phrases to experiences everyone can relate to, in this way they will feel included and not different or singled out because of their different level of speaking English. 

The question inquiring about the school before enrollment in these schools, your son and you can ask about the other schools out there that language either the language of the city, students can enroll in any training center for language learning

Say it in English and then again in Arabic. Reassuring that they take notes and understand what the vocabulary or definition of that word is. Some kids will feel embarrassed to speak English for fear of getting mocked. After that particular lesson is taught have a student reiterate what was just discussed. Pick the non English speaking student first to answer the question and hopefully it will set off an integrated learning experience.