What would you call the people who lived in Palestine?A

Map of the British Mandate

Source: Jewish Virtual Library

After World War I, the Ottoman Empire was broken up and the League of Nations assigned the British with a mandate over "Palestine" which came into effect in 1923 and remained until in effect until 1946. According to Wikipedia:

With the League of Nations' consent on 16 September 1922, the UK divided the Mandate territory into two administrative areas, Palestine, under direct British rule, and autonomous Transjordan, under the rule of the Hashemite family from the Kingdom of Hejaz in present-day Saudi Arabia

According to the Online Etymological Dictionary the origin of the word "Palestine" is:

from L. Palestina (name of a Roman province), from Gk. Palaistine (Herodotus), from Heb. Pelesheth "Philistia, land of the Philistines." Revived as an official political territorial name 1920 with the British mandate.

It as Newt Gingrich seems to believe, the Palestinians are an "invented people", the invention is an old one with considerable justification in historical nomenclature. They may be Arabs in the sense that they speak Arabic, as people in many nations share a bond of speaking English, but the other nations that speak Arabic have generally not granted Palestinians citizenship.