well I am not a teacher. a doctor at my university who taught in japan told us that you have some problems in speaking because you dont have some of the english letters. But he said that this is not your main problem, your main problem is that you are shy to participate because making a mistake in japan is a big shame.
so my advice to you is just to talk without fearing to make mistakes. it is normal to make some as we are not a native speakers.
maybe in arabic we have most of the sounds in the english. thats why the teacher is saying that the arabic and farsi people are the best foreigns in speaking. but if you tried you shall learn.