Pages/AppleScript: Delete (keep) paragraphs with a specific language

-- https://macscripter.net/viewtopic.php?pid=206979#p206979

use AppleScript version "2.4" -- Yosemite (10.10) or later
use framework "Foundation"
use scripting additions

set theLangs to {}
tell application id "com.apple.iWork.Pages" -- Pages
tell document 1
set theParagraphs to paragraphs of body text
repeat with i from (count of theParagraphs) to 1 by -1
if length of item i of theParagraphs > 1 then
set theLanguage to (my guessLanguageOf:(item i of theParagraphs))
-- will be "en", "de", etc
if theLanguage = "en" then
delete paragraph i of body text
end if
end if
end repeat
end tell
end tell

on guessLanguageOf:theString
set theTagger to current application's NSLinguisticTagger's alloc()'s initWithTagSchemes:{current application's NSLinguisticTagSchemeLanguage} options:0
theTagger's setString:theString
set languageID to theTagger's tagAtIndex:0 |scheme|:(current application's NSLinguisticTagSchemeLanguage) tokenRange:(missing value) sentenceRange:(missing value)
return languageID as text
end guessLanguageOf: