The Classical Arabic language as recorded was a poetic koine that reflected a consciously archaizing dialect, chosen based on the tribes of the western part of the Arabian Peninsula, who spoke the most conservative variants of Arabic. Even at the time of Muhammed and before, other dialects existed with many more changes, including the loss of most glottal stops, the loss of case endings, the reduction of the diphthongs /aj/ and /aw/ into monophthongs /eː, oː/, etc. Most of these changes are present in most or all modern varieties of Arabic.