2.1.671 Part 1 Section 18.4.3, phoneticPr (Phonetic Properties)

a.   The standard states that the type attribute specifies which type of East Asian character set should be used to display the phonetic run.

Excel uses this attribute to specify which Japanese character set should be used to display the phonetic run.

b.   The standard states that phonetic text is allowed for East Asian languages.

Excel restricts phonetic text to the Japanese language.