Diretamente da Apple, diz que você pode usar o escape:
Opção 1:
caracteres especiais de string
The backslash (\) and double-quote (") characters have special meaning
in text. AppleScript encloses text in double-quote characters and uses
the backslash character to represent return (\r), tab (\t), and
linefeed (\n) characters (described below). So if you want to include
an actual backslash or double-quote character in a text object, you
must use the equivalent two-character sequence. As a convenience,
AppleScript also provides the text constant quote, which has the value
\".
Table 6-1 Special characters in text Character To insert in text
Backslash character (\) \ Double quote (") \" quote (text constant)
Opção 2
Na mesma página, a Apple diz que você pode usar quote
para inserir \"
:
set myString to "this is a " & quote & "quoted" & quote & " text."
Opção 3
Outra opção encontrada é:
set inString to "quoted"
set myString to "this is a " & quoted form of inString & " text."
Editar: No entanto, você disse que o último resultado é de this is 'quoted' text
.