People use both Latin and Arabic script to transcript Tunisian Arabic, I think this should be reported. As for Latin script, it can be seen with the usage on internet of the language, done by its speakers. In this case diacritic signs such as 9 7 or 5 are used to replace missing sounds. Also the same method, with a latin script is used on TV channels and emissions (as information feed) and as well on sign boards. As researches to back the matter, we can see among others: -Younes, J., & Souissi, E. (2014). A quantitative view of Tunisian dialect electronic writing. 5th International Conference on Arabic Language Processing, CITALA 2014) and -Boujelbane, R., Khemekhem, M. E., & Belguith, L. H. (2013). Mapping rules for building a tunisian dialect lexicon and generating corpora. In Proceedings of the International Joint Conference on Natural Language Processing.
We will add Latin script as a writing system for Tunisian Spoken Arabic [aeb], with the comment "Informal use in social media" for the 19th edition of the Ethnologue.