strong-accent 

The strong-accent element indicates a vertical accent mark.

Element Information

Model

Attributes

QName Type Fixed Default Use Inheritable Annotation
color color optional
default-x tenths optional
default-y tenths optional
font-family comma-separated-text optional
font-size font-size optional
font-style font-style optional
font-weight font-weight optional
placement above-below optional
relative-x tenths optional
relative-y tenths optional
type up-down up optional

Source 

<xs:element name="strong-accent" type="strong-accent">
  <xs:annotation>
    <xs:documentation>The strong-accent element indicates a vertical accent mark.</xs:documentation>
  </xs:annotation>
</xs:element>

Sample