This paper is an overview of the pioneer contributions of David Cohen to Maltese synchronic and diachronic phonology. The focus is on four critical issues in this domain: the evolution and the phonological status of the pharyn-geal fricative għ and the laryngeal fricative h; the influence of the " emphatic " and " back " consonants on the development of the current vocalic system; the raising and fronting of the back short and long vowels a and ā traditionally termed imaala; the historical phonology of the oldest written Maltese poem, the Cantilena. Cohen's works are presented within the general background of Ara-bic dialectology in which he was completely at ease, and briefly compared with other scholar's work on the same topics.