emphasis Element (Microsoft.Speech)
Increases the level of stress (prominence) with which the contained text is spoken.
Indicates the strength of emphasis to be applied, using one of the following enumeration values: strong, moderate, none, reduced. The default level is moderate.
The speech synthesis engines for the Microsoft Speech Platform SDK 11 do not support the emphasis element at this time. Setting values for the level attribute will produce no change in the synthesized speech output.