Note 1: To confuse matters further, linguists seem to claim that what they mean is that Lebanese doesn’t descends from the Southern Semitic Classical Arabic, but from some abstract hypothetical construction anachronistically called Central Semitic Proto-Arabic, itself very different from Classical Arabic. But calling this “Arabic” is what is confusing the crowd. Naming causes framing. So if they don’t mean “Arabic”...
It would be an anachronism to assert that Italian is a dialect of Catalan, but safe to say that Italian comes from Latin. But when it comes to Lebanese (more generally NorthWestern Levantine), the “politically correct” Arabist-think-tank view is that is is derived from Arabic (Lebanese “dialect” of Arabic) to accommodate sensitivities?—?even linguists find arguments to violate the arrow of time to serve the interest of panArabism. In situations where there are similarities between a word used in Leb and Arabic, they insist it comes from Arabic not from a common root of both. (Most Lebanese are confused by diglossia as one is not supposed to write in the spoken language). Unlike Indo-European languages, Semitic languages have a criss-cross of roots and considerable areal diffusion to assert clean descendance, hence statements such as “A is a dialect of B” don’t have the certainty and neatness found elsewhere.
The points here are 1) Lebanese (more generally NorthWestern Levantine, neo-Canaanite) is to be treated as a standalone Semitic dialect (or language) that descends from other languages, including Arabic (which itself was influenced by same predecessors) but has not inherited from it as much as marketed (broken plurals but not its rich verb forms). 2) Its grammar as we will see below remains largely nonArabic. Many words that are in both Leb and Arabic but not common in Aramaic happen to be in North-Phoenician (Ugaritic). Unlike genetics that has rigorous mathematical formulations and clear-cut flows (haplogroups show direct, vertical, rather than lateral transmission), linguistic categories are fuzzy and, for Semitic languages, monstrously unrigorous. 3) Its vocabulary predates Arabic (even in cases where we got the Arabic innovations). I took a list of the most frequent statistically used words (by Zipf law, > 80% of vocabulary) and looked for words that exist in both Leb and Akkadian, Ugaritic (North Phoenician), and show that very very few exist in Arabic but not other Semitic roots, hence could have only come from Arabic. (Lamine Souag did the same with a poem by Said Akl, without statistical methodology).
4) The “Arabization” mission promoted by the American University in Beirut in the 1860s (starting with the (re)translation of the Bible) seems to infect the most low IQ Westerners of the think tank/ State department Arabist types, (Western losers you meet at conferences) not locals?—?most people who disagree with the point and support the orthodoxy don’t speak either Leb or Aramaic, or fail in basic reasoning (many Syriac scholars I’ve spoken to sort of agree with the point)More here