In Israel I've found that Hebrew speakers exclusively write in Hebrew. Aside from letters, there's nothing else needed. One CAN add vowels, but only children's books have vowels so we're used to reading without them.

The Arab world uses a lot more of the Latin alphabet, but they don't write in English. For example مرحبا would turn into mar7aba. Here's a wikipedia article on the phenomenon. https://en.wikipedia.org/wiki/Arabic_chat_alphabet#Levantine...