I've been using OpenWrt since the heady days of Whiterussian on a Linksys wrt54g.
The "wrt" standing for "wireless router".
I think the OpenWrt naming stems from that device, maybe some one as old as me will remember if that is true
Hailing from the UK, I have always pronounced OpenWrt as "OpenRoot".
I have heard others saying "OpenRowt".
But recently I have heard in some Youtube videos "Open Doubleyou Arrr Teee".
This last one does not seem right to me. Apart from being cumbersome, it implies "OpenWRT", whereas the first two seem very logical given regional pronunciation differences of the English language.
It definitely depends on the native language: It used to be Open (as in English) WRT (three individual German letters) for me. In recent years I've changed to "Open Doubleyou Arrr Teee".
Yes, mixed language pronunciations, particularly in science/technology fields can be confusing - unless of course by common usage it becomes a de-facto standard
In German Language i use most of the time Open W R T (german pronounciation).
But technically its bot easy possible to find a „correct“ one, as the Wrt is not a correct short term.
Maybe Open Wireless Router?
I think it is not so much an incorrect term, but simply part of the OpenWrt Registered Trade Mark.
The original meanings of the letters W, r and t are long forgotten.
I'm used to say "Open doublevé air té" in french and "Open double u ar tea" in english. I try to stick with the natural pronoucation in each language. I assume you can do the same with other languages. As long as your interlocutor understands you, no worry.