For the discussion of a modal framework of the Christian Arabs in Israel - termed "Lachan", 230 melodies were examined each sung at least twice by 28 research participants. The most constant factor when defining the "Lachan" by all the research participants were the central notes which are included in the typical musical motives. The central notes divide the Lachan's scale to smaller typical groups trichords, tetrachords and pentachords. The intonation of some of the Lachan's scales is complex but interesting. A unifyed scale system of all the "lachan"s (such as that of Gregorian modes) is absent and differs among the research participants. However the differences are restricted within "tonal skeletons".