The purpose of this paper is to explore the properties of Arabizi as a system with a ‘bottom-up’ orthography that emerged in the specific context of Computer-Mediated Communication (CMC). The study focuses on the dialects spoken in the city of Nazareth and the villages surrounding it (N = 75). We examined the consistency of choice of Latin letters and Arabic numerals for Spoken Arabic (SA) phonemes from two complimentary perspectives: subjective reports and the corpus-based analysis of a unique writing sample in Arabizi, elicited texts. Our results show a consensus on conventions in the transcription process, with some expected variation reflecting differences between regional dialects. This indicated a high degree of normativization or standardisation in Arabizi orthography.