@java.lang.Override
    public java.lang.String getMarkup() {
      java.lang.Object ref = "";
      if (inputSourceCase_ == 5) {
        ref = inputSource_;
      }
      if (!(ref instanceof java.lang.String)) {
        com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
        java.lang.String s = bs.toStringUtf8();
        if (inputSourceCase_ == 5) {
          inputSource_ = s;
        }
        return s;
      } else {
        return (java.lang.String) ref;
      }
    }
<pre>
Markup for HD voices specifically. This field may not be used with any
other voices.
</pre>

<code>string markup = 5;</code>

@return The markup.
java-texttospeech/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/StreamingSynthesisInput.java