I like this idea. But I am not sure about its ease of use. There is a much less precise but significantly speedier way to convey Arabic words using the Roman alphabet on a QWERTY keyboard using the Arabic chat alphabet. [1]. The more difficult sounds in Arabic are conveyed with numbers. For example ح is 7 - and ع is 3. In both cases the Arabic letters are visually similar to the character that represents them.
[1] https://en.wikipedia.org/wiki/Arabic_chat_alphabet