They are using different liturgies.
Alexandrian
Liturgy of Saint Basil (Coptic)
Liturgy of Saint Mark (St. Cyril)
Liturgy of Saint Gregory of Naziansus
Antiocene
Liturgy of Saint James
Armenian
Liturgy of Saint Gregory (Armenian form of St. Basil)
Byzantine
Liturgy of Saint Basil
Liturgy of Saint John Chrysostom
Liturgy of the Presanctified Gifts
Liturgy of Saint James (once a year by some)
Chaldean
Liturgy of Mar Addai & Mar Mari
Liturgy of Mar Theodore of Mopsuestia
Liturgy of Mar Nestorius
Latin
Mass: ordinary and extraordinary forms, Ambrosian, Braga, Mozarabic, Carthusian,etc.
Antiocene → Chaldean
Antiocene → Byzantine → Armenian
Antiocene → Gallican
Antiocene → Latin, + Gallican → Latin
Antiocene → Alexandrian → Coptic
Antiocene → Alexandrian → Abyssinian
Alexandria and Antioch are the starting-points of the two original Eastern rites.
The earliest form of the Antiochene Rite is that of the “Apostolic Constitutions” written down in the early fifth century. From what we have said it seems that this rite has best preserved the type of the primitive use. From it is derived the Rite of Jerusalem (till the Council of Chalcedon, 451, Jerusalem was in the Antiochene Patriarchate), which then returned to Antioch and became that of the patriarchate.