This article attempts to give a summary of the contribution made by early Arabs and Muslims in the field of phonetic sciences. Works by scholars like al-Khalīl (d.175/791), Sībawayhi (d.177/793), Ibn Jinnī (d.392/1002), Ibn Sīnā or Avicenne (d.428/1037) and others will be given special attention in this connection. In particular, it presents the various treatments of the Arabic nasal sounds and the phenomenon of nasalization. As a term of reference, the Arab and Muslim phoneticians divided the Arabic phonemes into categories such as: glottals, pharyngeals, palatals, dentals /l, r, n/, and labials /f, b, m, w/. Al-Khalīl is one of the first Arab phoneticians to order the Arabic phonemes in terms of place of articulation along the vocal tract from the glottis upward to the lips. His student, Sībawayhi, and later phoneticians also recognized other categories in terms of manner of articulation such as: voiced/voiceless, stop/ non-stop, rolled, lateral, nasals/m, n/, including variants, e.g. [ŋ, N]. Further, Sībawayhi and Ibn Jinnī seem to lay more emphasis on treating ghunna or nasality and other features in terms of binary distinctive feature analysis. The Muslim phoneticians also recognized that in certain contexts /n/ and /m/ may influence non-nasals, both vowels and consonants. In sum, a close look at the early Arab grammatical works reveals an underlying systematic approach and a rich mine of terminology which are relevant both to modern Arabic phonetics and general phonetics. Some instrumental (spectographic and mingo-graphic) data are included at the end of the article in order to support some of the descriptive techniques used in early phonetic heritage.