Semitic languages
The similarity of the Hebrew, Arabic and Aramaic languages was accepted by Jewish and Islamic scholars since medieval times. The languages were familiar to Western European scholars due to historical contact with neighbouring Near Eastern countries and through Biblical studies, and a comparative analysis of Hebrew, Arabic, and Aramaic was published in Latin in 1538 by Guillaume Postel. Almost two centuries later, Hiob Ludolf described the similarities between these three languages and the Ethiopian Semitic languages. However, neither scholar named this grouping as "Semitic".
Moab
Most of our knowledge about Moabite comes from the Mesha Stele, which is the only known extensive text in this language. In addition there are the three line El-Kerak Inscription and a few seals. The main features distinguishing Moabite from fellow Canaanite languages such as Hebrew are: a plural in "-în" rather than "-îm" (e.g. "mlkn" "kings" for Biblical Hebrew "məlākîm"), like Aramaic and Arabic; retention of the feminine ending "-at" or "-ah" which Biblical Hebrew reduces to "-āh" only (e.g. "qiryat" or "qiryah" "town", Biblical Hebrew "qiryāh") but retains in the construct state nominal form (e.g."qiryát yisrael" "town of Israel"); and retention of a verb form with infixed "-t-", also found in Arabic and Akkadian ("w-’ltḥm" "I began to fight", from the root "lḥm".)