The documentation "babel.pdf" has a typo in the Example for "main" on page 30.
(This was part one of the problem reported in the now closed #219.)
Let’s assume your document (xetex or luatex) is mainly in Polytonic Greek with but with
some sections in Italian. Then, the first attempt should be:
`\usepackage[italian, greek.polutonico]{babel}`
The language attribute for polytonic Greek in the contributed Babel-Greek package is
"polutoniko", not "polutonic".
(This may explain why some accents in Greek are not shown correctly after specifying this option.)
The documentation "babel.pdf" has a typo in the Example for "main" on page 30. (This was part one of the problem reported in the now closed #219.)
The language attribute for polytonic Greek in the contributed Babel-Greek package is "polutoniko", not "polutonic". (This may explain why some accents in Greek are not shown correctly after specifying this option.)