The paper discusses the relevance of the 18th-century Catalan-Maltese _Vocabulary_ by Marquis de Sentmenat to a number of issues pertaining to the historical phonology of Maltese. The topics addressed are the following: word-medial _imāla_ of */a:/; deletion of short unstressed vowels in word-initial open syllables; auxiliary vowels; interdental fricatives; regressive voicing assimilation in obstruent clusters; word-final obstruent devoicing. The accuracy of the data in de Sentmenat's _Vocabulary_ is evaluated in light of corroborating evidence adduced mainly from other 18th-century records of Maltese.