The English-speaking World Discovers #Subtitles Episode 37 (as always, accompanied by #SquidGame stills):
"As audiences embrace subtitles, translated series have become more common, particularly on streaming services. "
#subtitlingheadlines
by @vulture
https://www.vulture.com/article/localization-translation-international-streaming.html

#Subtitlers are always grateful to see their work portrayed and explained, especially in such detail, but let's see some inaccuracies here👇

"localization starts with a revised script often referred to as a 'template'".
The template is not a script, but a timed text, a subtitle file - edited, positioned, researched, annotated - intended as a basis for all translations. Not necessarily a verbatim transcription.

The #subtitlingtemplate is based on the post-production script, if present, ideally including everything the article describes: "notes to explain the context of certain cultural phrases, words, slang terms, honorifics".
So, localization ideally starts from the client script.

"Building a #subtitle barrier"
That's a nice play on Bong Joon Ho's words, but this is not what we try to do. Most subtitlers like to think they remove language barriers.

And here's some messing up of terms
"The style guides used by Netflix and Disney+ specify that the number of English subtitle characters that can be displayed onscreen at any given moment — known as 'line segmenting' — is 42 per line"

'Line segmenting' is breaking the lines at logical points, whether within the same subtitle (up to two lines) or between two subtitles.
What the article refers to is known as "characters per line".

There is also the "characters per second" specification, which is probably what the author tries to explain, very unsuccessfully, here:
"the exact number of frames a line of dialogue can be onscreen before moving onto the next line — “timing” — is 20."

"Timing" is defining the in and out times of the subtitles. Depending on the specifications, it can be a complicated task, based on many (sometimes contradicting) factors.