And lastly, I have heard from some Ethiopians that there is a Coptic influence on their Church - I am still not sure what they mean. And I have seen a Ethiopian Orthodox site that has a section called Struggle for Autocephally:
ethiopianorthodox.org/gallery/todaysphoto/struggleforautocephally/index.htm
This is not really an example of changes to a given liturgy or church. Ethiopia
originally received her anaphoras from Alexandria, and her first bishops came from the Alexandrian Church, as well (sent by HH Pope St. Athanasius the Apostolic). It is true, though, that the Orthodox Tewahedo Church was administered by the Copts for 1600 years or so. It didn’t get its own bishops until the time of Pope Yusab II in the 1940s-1950s (this is apparently why the Ethiopians do not recognize his deposition, even though the rest of us do). So in the case of the Ethiopian Church, autocephaly itself was the change, but did nothing to change the essential character of the Church or its liturgies. It developed alongside the Coptic Church, of course, being so intimately tied to it (writings by Coptic popes, for instance, rightly refer to the EOTC as the daughter Church of the Coptic Church, though Ethiopia was originally evangelized by Syriacs), but it always had its own national character (in its own language, with its own chant form since at least the days of St. Yared in the 6th century, etc.), long before it had its own national/ethnic bishops.
With regard to the Coptic and Ethiopian relationship, one thing that
is a change (or
was, rather) was the practice of sometimes celebrating the “Habesha Liturgy”, as they called it, in the Coptic Church. This was a translation of the Ethiopian liturgy (not sure which particular anaphora) into Arabic, as was common in past eras, for celebration in Egypt. This practice was apparently banned under HH Pope Shenouda III on the grounds that the Copts ought to only celebrate with their native liturgies (the Basilian, Cyrilian, and Gregorian), and not those of other churches, even if we’re in communion with them. I agree with him on this account (imagine, for instance, how inappropriate it would be for the Maronites to celebrate according to the Melkite liturgy), but still find the
one recording I have heard of the “Qiddas el-Habashi” to be incredibly beautiful. But of course this was a Copticization/Arabization of another’s liturgy (as the EOTC liturgy
as celebrated by actual Ethiopians is nothing like what you hear at the previous link), and hence inappropriate for
both peoples…but it is still an interesting bit of history in the relations between the two churches of great antiquity and holiness.
There are other examples of changes to the Coptic Orthodox liturgy proper (or at least the practice of it, rather than its content), such as the introduction of the cymbal and triangle, which I’m told came into use circa 12th century AD (and, indeed, early Alexandrian witness shows great antipathy to these instruments; early saints wrote of the cymbal as emblematic of pagan worship, and thoroughly unsuitable for worship in the Church; um…oops) as a means of time-keeping because the Copts were rapidly losing their language at that time, resulting in a consequent precipitous decline in the ability of the people to handle the complex rhythms and cadences of Coptic chant. I don’t know how true that is (it’s just an explanation I’ve heard), but it seems to be reflected even in the modern day use of the cymbals, which only ever come out in my church when we have lost the rhythm of a particular chant…

(and in Holy Week, due to the very different, very complicated and long melodies used at only that time of year…they’re difficult to keep up with even with the cymbal to help us keep time, honestly)